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Table of Contents

How to Install Glass Blocks Professionally

From Estimating, to Layout, to Installation

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This page was written by an experienced glass block installer and contains tips, tricks, and shortcuts that will save you time and money, ensure a smooth work flow, and a beautiful finished product. As I have retired from the trade I am willing to pass on my trade secrets. Laying glass blocks is a specialty trade. I will teach you how to do this, and business strategies to get you top dollar and maximise your productivity. If you are a home owner and wish to try your hand at laying glass blocks, it is something that can easily become a disaster. However if you read this page and take your time, you will greatly increase your chances of success. But if you go fast or your ego assures you that you are capable of anything, you risk expending time and money on something that will have to be replaced.

If you are learning the art of laying glass block, the tips here and your practical application of them, will accelerate your learning curve towards being a professional to whom no job is too big. Here you will learn how to install glass block windows, how to build a glass block shower wall, and how to estimate materials.

The main reason that most home owners and many bricklayers have problems with them, is that the basic premise of building with masonry units (brick, concrete block) is that they absorb the moisture in the mortar. The glass block absorbs no water so does not perform to the expectations of most people. For this reason alone this guide will save you years of experience as you will learn methods of laying glass block that will both increase your productivity and make your job far easier.

One common complaint with a poor glass block installation, by a poor tradesman or rough home owner, is leaks during rainy periods. I have never had a leaky window ever, and even guarantee my work to be leak free for the owners lifetime, barring catastrophic damage such as a major earthquake or a car hitting the house. I will teach you to use the same methods I did, so that you will have the confidence to say the same thing.

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The History of Glass Blocks

Glass blocks date back to the 1800’s. The first glass blocks were used in ships to allow light in the sides. These had a prism in them to scatter the light over a larger area.

During the 1880’s glass was blown were blown into geometric shapes and used in non structural masonry construction. The problem with these was that they weren’t sealed so moisture would seep in and condensation would form.

In 1903 the Lubber Machine revolutionised glass making. In 1907 a patent was filed for the first standardised glass blocks. These were designed to be used in conjunction with reinforced concrete and hollow beams (which were also in their infancy). These blocks had a glass plug inserted in them to prevent condensation but it wasn’t very efficient.

In 1930 Corning–Steuben (which has now become Pittsburg–Corning) created a sealed glass block by placing two halves of heated glass together. This process is used to this day.

Manufacturing

Glass blocks are still made of two pieces – a male and a female side. These are pressed together at 800 degrees Celsius to form the block. As the glass is created hot, the inside is under a reduced pressure. The advantage of the reduced pressure is that the block, should it break, will implode and not cause as much mess or potential hazard.

Pittsburg–Corning blacks are manufactured in a nitrogen environment which ensures that the interior of the glass block is filled with an inert gas.

Manufacturers of Glass Block

There are two major manufacturers:

1. Pittsburg–Corning (USA) 2. Weck (Germany)

There are a variety of sizes and patterns available. The Weck glass blocks also come in various colours.

As this guide was written by some one who installed glass blocks in the USA and the most popular and common glass block in the USA is Pittsburg–Corning, all the sizing and dimensions in this document will refer to Pittsburg–Corning glass block. For Weck glass block the basics are the same but the sizing will be in metric, and the selection of sizes, patterns, and types of glass blocks will be different.

It is important to remember that glass blocks are not structural building units – i.e. – they can’t bear weight. They are decorative only.

Sizes

The Pittsburg–Corning Glass blocks come in Imperial measurements (inches) and the Weck glass blocks come in metric sizes.

Pittsburg–Corning has a number of sizes and two widths.

The most popular size is 8×8” but they also are available in 6×6”, 4x 8”, 12x 12” and there are also end blocks and corner blocks.

The 6x 6” and the 8x 8” are available in the lightweight ‘Slimline Series’ which is 3” wide. The Slimlines are only designed for interior applications and in most areas will not meet building codes for external uses.

The 4” thick glass block is the standard width and is available in 6x 6”, 4x 8” , 8×8”, and 12×12”.

The 12×12” sizes are designed for commercial and industrial applications and do not look aesthetically pleasing in a residential setting, although some people will have them installed to save a bit of money. They still don’t look right in this setting, and most home owners realise this after they have been installed.

The most popular size is the 8×8 inch glass block in a 4 inch width.

Types of Glass Blocks

  • Slimline Series

Apart from the Slimline series which is designed for internal use only, there are several other styles.

  • Standard Series

These are four inches width and designed for internal or external use. These are available in 6×6, 8×8, 4×8, and 12×12.

  • Sixty Minute Fire Proof Rated Glass Blocks

These are a heavier block with thicker sides and are fire rated for sixty minutes.

  • Ninety Minute Fire Proof Rated Glass Blocks

These have even thicker sides and are fire rated for ninety minutes, which is often required on commercial and industrial buildings.

  • Solid Glass Blocks

These have two main applications.

These glass blocks are bullet proof and can be used in high security environments. These glass blocks are see through and provide good visibility.

These glass blocks can be used as a walkway if a load bearing iron grid frame is used to support the blocks.

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Patterns

The most popular pattern is called ‘Decora’ and has a wavy appearance. It lets most of the light through but disperses it around the room, lighting up a maximum sized area. It also provides privacy as it can’t be seen through. If you put your face against it and had your hands around your eyes, you would have some vision inside but it would be very much distorted.

There are a variety of other patterns such as Vue which is clear and you can see through, but doesn’t disperse the light.

Other patterns are retro, and the fire rated glass blocks come in Decora and also a grid pattern.

If you are using a block with a pattern, as some have vertical lines on one side, and horizontal lines on the other, you should ensure that when they are installed the lines are consistent and go in the direction you desire from each side, or are set in a checker board pattern.

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Decora blocks used in a shower.

Building Codes

Building codes change over time and there are different building codes in different parts of the country, or in different countries. It is your responsibility to ensure that your window or shower complies with the relevant building codes in your area.

In addition if you are installing them yourself, the onus is on you to have pride in your work and in the construction of your wall or window. In addition to building codes, the rate of installation can be increased in many cases by adding more anchors than the building code calls for. An efficient glass block installer knows the tricks that will increase his productivity and the cost of additional reinforcing is minimal compared to the profits that can be made by installing a structure in a shorter amount of time, including the cost of a helper. It also ensures that your glass block window or panel not only meets the building code, but surpasses it.

Glass Block Installation Tools and Equipment

Everything listed here will ensure you are able to tackle any project, from windows and showers, to replacing broken glass blocks. Although not everything is required, all items will come in useful in situations you deal with day in and day out.

Tools

A good quality trowel such as one manufactured by Marshalltown. Put a rubber tip from a cane on the end of the handle. This allows you to use the handle to gently tap blocks without a hard impact.

A brick hammer for chipping cement off floors or openings.

A good quality heavy claw hammer for nailing and pulling out nails.

A rubber mallet. This is one of the most essential tools for glass block installations.

A good quality electric drill for attaching screws to hold anchor bolts in wood. You’ll also require a selection of various size drill bits and screwdriver bits. Ensure you have lots of extras as they break and get stripped. The advantage of an electric drill becomes apparent when you are working on a ladder or scaffold.

You’ll require a heavy duty drill/chipping hammer. This will drill holes in cement or concrete, and the chipping hammer is good for cleaning cement debris from a concrete opening. You’ll need cement drill bits and a few sizes of blades for chipping.

Tuck Pointers (also called slickers) in several sizes. The ones under ¼ inch wide are especially useful.

Several jointers. These aren’t used a lot as there are a few tricks to finishing your joints that don’t require the use of a jointer, but you will sometimes encounter hard joints and a jointer can remove the excess quickly and easily.

A paddle wheel mixer for mixing cement in buckets. Always have an extra paddle available in case it breaks. A cheap powerful drill (about $40) will do the job if your paddle mixer breaks, but it won’t last long. The drill will pay for itself in that case as the lost time on the job will add up fast. Always mix on a tarp.

Pliers.

Long handled heavy duty wire cutters to cut galvanised reinforcing rod.

Tin snips. These must be heavy duty for cutting wall anchors as needed.

Grout bags. Most grout bags do not work very well but the plastic ones work great. These are inexpensive but extremely hard to find. When you come across them buy large quantities.

Sponges. You will need large quantities of these as they are used to wipe down the glass block, however as soon as they become damp they are useless. Try to have at least twenty sponges on hand, and after using them rinse them with water and set them somewhere to dry. On a large job that will go for several days, you will probably require more. If a sponge is not cleaned immediately, the cement or grout will dry and the sponge must be thrown away as it will scratch the glass block.

Steel wool – 000 grade. This is used in cleaning the glass block. However if you use anything coarser than 000 grade you will scratch the glass block.

Several five gallon buckets. You will use one for cement, one for finish grout, one for water where the glass block are being installed, and one for the mixing area. A couple of extra buckets are handy for cleaning sponges, holding materials, etc. You can pile them one inside the other when you are in transit to save space.

Extension cords. These will have to be heavy duty as your mixer will draw a good amount of power and you don’t want to have to keep flipping the breaker back on. Sometimes you maybe be running accord a long distance so having two heavy duty fifty foot cords is ideal. Try to get the ones that light up at the plug in end when they have power. This will save a lot of time trouble shooting if you are having electrical problems. You’ll also need a power strip with multiple outlets to attach your radio, etc. A few shorter extension cords are handy to run power up scaffolds or ladders.

Ladders. You will need at least a good quality folding ladder. If you are working at heights you will require an extension ladder. Scaffolding is not used often enough to justify the cost and can be rented.

A good quality dolly to pile up your materials and move them around. Essential! Your helper may be willing to do it, and will have to if there are stairs, but you will need him in good form all day as installing glass block is a labor intensive process.

Wheelbarrow. Handy for moving materials around, especially bags of glass block cement.

Painters tape – thick width rolls of paper tape are great for taping around a finished opening to keep it clean. Once you glass block installation is complete, you can peel off the painters tape and the finished (painted) wall is clean and has no dust. A great time saver.

Duct tape. Essential for many purposes. Have lots on hand.

Rope. You will find lost of uses for this so have plenty on hand.

Tarps. Use tarps wherever you are mixing your cement. Whether you are in a carpeted area, a job site, or a lawn outside a building, a tarp greatly reduces the amount of time and labor to clean up. Extra tarps are handy for covering materials or your workspace when you go home for the day. Spare tarps can be used to cover your glass block wall or window should it rain. Duct tape, nails, and screws can hold it in place.

Nails and screws in a variety of sizes and lengths. They must be galvanized.

Plastic disposable drop sheets. These must be a decent thickness. If you get them too thin they will rip and pull apart and you are back to manually cleaning. Clean up is very time consuming and glass block cement and finish grout are vary dusty and hard to clean. Placing drop sheets on both sides of where you are working, where your materials are piled when you are working, under all bags of cement and grout, ensures that when you are finished you just ball up the sheet and throw it out. You’ll also need lots of heavy duty garbage bags.

White vinegar. Have several bottles on hand, As the cement and finish grout is a base, the vinegar is useful in cleaning freshly laid glass block and you can pour it on your hands periodically to ensure they don’t get too cracked. Even with rubber gloves you should rinse your hands periodically though out the day to keep your hands useable. Don't work without it!

Mortar boards. These can be made from plywood and should be about two feet square. Different sizes are useful for different situations where you have space demands.

Small buckets such as sturdy yogurt containers. These are handy for placing dry glass block cement in. This will be discussed later as a time saving trick.

Water bottles, to pour water in your glass block cement to make it more useable.

A radio. Listening to music helps you get in the zone and makes the job far more pleasant. My rule on the job was – no music, no work!

Construction pencils, knives, etc.

Circular saw.

Tape measures.

Levels: A four foot and a two foot level. You’ll also need an eight inch level to check for blocks in the first course to ensure they are level. A longer eight foot level is handy at times and if you are going to do this full time or have a large opening you should have one of these on hand.

Shims. Plastic shims are handy when dealing with uneven surfaces or you run into problems (maybe there have been some impacts caused by other trades, or vibration from a road which have cause your blocks to move). Cedar shake makes good shims as it can be broken into small pieces for different size requirements. Always make sure your shims stick out enough to be able to be pulled out later.

Safety Equipment

Ear protection for you and your helper.

Safety glasses for when breaking glass or cleaning up broken glass.

Several packages of rubber gloves. The glass block cement and finish grout will dry your hands out in a few hours. Then your hands will crack and bleed. Using disposable gloves and replacing them as needed will ensure you finish the day pain free and are able to work as efficiently the next day.

Work gloves for carrying material such as reinforcing rod, etc around. This is especially helpful when loading materials from the supplier and unloading at the job site.

First aid kit including tweezers, band aids, bandages, and tourniquets for deep cuts. Working with glass you will get cuts. Note - I have never had to use a tourniquet, but it's better to have it and not need it, than not have it when needed!

Installing Glass Block in a Window Opening

Sizing

First you have to have an idea of the finished size you desire. The eight inch glass block is actually 7 and ¾’s inch by 7 and ¾’s inch. This allows for a ¼ inch spacer to ensure a uniform joint size which is created by using spacers. This means that you will be measuring in increments of eight inches.

So each eight inches includes one block and one joint. But when you finish a course (a row of blocks) you will have another joint that hasn’t been accounted for. This means that you have to add another ¼” to your dimension.

So if you have a window opening that will be eight glass blocks wide by eight glass blocks high, it should be 64 and ¼ inches by 64 and ¼ inches.

This is calculated by adding the number of glass blocks required to go from side to side and adding an additional ¼ inch.

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It may seem I am repeating myself here but it is crucial that the opening be the correct size. If it is too small you will have to redo the carpentry work and start over (not likely) or do more carpentry work to make a smaller opening to accommodate seven by seven glass blocks.

Quiz: And what size would a seven glass blocks by seven glass blocks opening be?

Answer: forty and ¼ inches by forty and ¼ inches.

  • Tip - ensure that the sides of the opening are plumb and level. If your opening is not vertical, as the glass blocks use a spacer system for the joints, your window either won’t fit, or the out of whack side will definitely be visible to the eye as crooked, as the glass blocks are in a fixed grid and straight lines don't lie.

Construction

Your finished opening should be level on the bottom surface especially. If it isn’t the weight of the glass blocks will cause sag in the window. I will cover some tips to defeat this later, but for now just try to ensure the bottom piece of wood is level.

Your sides of the window should be double thickness 2×4’s or more as per building code, with a header beam across the top. It is essential hat a header be used as glass blocks are not structural (load bearing) and will crack if they have to support weight.

You should have uprights under the bottom window frame to support the weight of the glass block. Glass blocks, masonry cement, and reinforcing are extremely heavy and you won’t want a structural problem down the road or during installation. A good installer will measure and look at the openings for any issues prior to starting work.

Ensure that the wood is flashed. This means that there is a vapor barrier between the wood and the cement (or expansion strip). This could be black felt paper, rubber sheet (one sides sticks), or other suitable material. At no point should cement ever touch wood. Cement always absorbs water to some degree and exposed wood will wick it away, and the wood will rot.

Installing the Glass Block

After you have measured your opening and ensured it is the correct size, and level and plumb, you are ready to start. If there are issues notify the supervisor or home owner before starting work. Good communication goes along way towards customer satisfaction.

Before you do anything, place a drop sheet on the ground on both sides. It should be an adequate size for you to move around and have room for the materials around you. Tape your disposable plastic drop sheet to the immediate wall or surface where you will be working. Not only does this save you time, but the customer will be happy at the care and professionalism you show.

Arrange your tools on the floor in area off to the side, where each can be easily seen and picked up. Get all your electrical gear plugged in and ready for use. Tie your extension cords and drills together so they don’t come apart when you pull on them.

Turn the radio on. No music - no work.

Place flashing or vapor barrier on the wall if it’s not there already.

Measure your vertical distances on each side of the window in eight inch increments (assuming you are using 8×8 glass blocks) from the bottom up. Mark the intervals with your pencil.

These marks will be the top of each course of glass block where the panel anchors are to be attached. Building codes vary from area to area, over time, and between countries, but the basics remain the same. This marking of courses is very important, it allows you to visualise the construction before beginning.

Note - the use of expansion strips is required in concrete openings due to expansion and contraction due to temperature variations. They are also required in earthquake prone areas. This installation method will describe the installation of a glass block window without expansion strips. The use of expansion strips will be covered separately so as to keep the work flow easy to understand.

Even though your building codes may specify that panel anchors be used on only every second course of glass blocks, it is advisable to place them on every course. There are several reasons for this.

  • Panel anchors are cheap
  • Panel anchors on every course allow you to go faster (when experienced) as they provide more stability to the glass block panel.
  • It’s a good selling point. You can state that not only do you meet building code standards but exceed them.
  • The installation of panel anchors is greatly outweighed by the increase in productivity.

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The Panel Anchors

Panel anchors are strips of galvanized metal that are 24 inches long are as wide as the glass block is between the ridges. That is they lie hidden within the course of glass block.

A panel anchor must be bent at 90 degrees, a sharp bend, not rounded, and the resulting L shaped panel anchor is attached to the wall with galvanised screws. Most installers attach them as needed as they go. I have not found this to be an efficient method of attaching them, nor an efficient work flow. The problem is that stopping to place a panel anchor slows you down, it breaks your stride. That is not to say I don’t do it that way, I do at times, but I prefer the next method for the simple reason that any vibration can disturb your blocks setting in the cement. When the cement is almost set and it is disturbed, it can crack. The cracks will be minute but they increase the potential for leaks or instability as you work. When I say instability, I mean that as it sets, it is not rigid, and each tap on the block or the window can cause movement. If your glass block window is on an uneven surface, and it is not appropriately or properly shimmed, the window can form a bow to the downside, being the most noticeable in the middle. If this happens you will have to cease work, let it dry somewhat, and fix the issue. I will cover dealing with this issue later on.

A trick that I discovered along the way is to mount the panel anchors before you begin. This eliminates any potential vibration and once done can be forgotten. Having the marks provides the reference point they will be bent at.

The panel anchor should be bent so that when bent about six inches goes along the wall and the remainder is in the glass block panel.

If you are going to mount the panel anchors before starting work, you should mount them starting at the top and with them facing up. That is, mount the first one so six inches goes below your top mark and screw it in place. Attach the second panel anchor so that six inches of it is below the second mark from the top, and the rest of it overlaps the previous panel anchor. The only disadvantage of this is that your window now has metal panel anchors on each vertical side which you could scratch or cut yourself on. On a large glass block window it won’t make much difference to your mobility, but on a small glass block window you might have to mount the panel anchors as in the first method.

Regardless of which method you use, there is a standard for attaching the panel anchors. They should be attached with three galvanized screws, long enough to bite into at least 1 and ½ inches of wood and have a large enough head so at to not slip through the holes in the panel anchors. They should be drilled in so as that the three screws are staggered evenly and not in a straight line. If they are in a straight line the wood could split, but placing them in a non vertical line assures maximum strength.

Repeat – use galvanized screws.

Spacers

The spacers come in bags of 25. They are available in 3 inches wide or the standard 4 inches wide size. Make sure you get the right ones, especially as most glass block suppliers are far apart and you don’t want to return for any reason.

The spacers are designed to slide into the joint between the glass blocks. There is a square plastic tab on each side. When you are building you will want to leave these tabs on until you are ready to clean your glass block. They can be twisted off then. The tabs assist in holding your glass block panel firm as you are building it.

For the first course you will have to modify the spacers. Twist off the tabs (or look for broken ones in the bag) and once the tabs on both sides are removed, you’ll notice that the X shape (seen sideways), has a plastic spacer in one direction that can be broken off on each side. Remove these two pieces of plastic (but save them for later use) and now you can place your spacer on the bottom of the window sill and your glass blocks will sit in between them, when they are spaced eight inches apart.

Place your spacers along the window sill and place your blocks in (DRY) to ensure that they sit flat and are not too tight or too loose from side to side. Generally an opening has to be within 1/8 of an inch accuracy. While you are looking at it like this, and before you check the glass blocks with your eight inch level for tilt, place another row of spacers in the top of the glass blocks. This will hold it tight should you knock one off the window sill, and any tilt in the window sill be easily observed. Now get your big level (of a size that will go from side to side of the window or close to it) and straight line the glass blocks at the base of them. Straight lining means that you are using the straight edge of the level to nudge them into alignment. Do this from each side.

Now get your eight inch level and place it cross wise on the glass blocks in the middle of each glass block. Look at the bubble. All you need to do at this point is notice which way it slopes, if at all, and how much. When you start laying the glass blocks you can use shims and another trick I will describe shortly to get that first course right.

Reinforcing Rod

This comes in different lengths depending upon where you get it. Reinforcing rod is galvanized metal and looks like a ladder – there are two outside lengths attached by a cross member every sixteen inches. You cut your reinforcing rod so that it spans the length of your glass block window or wall. You should cut it an inch short at each end so that it doesn’t interfere with the spacers or panel anchors, and won’t protrude out of the end of a free standing wall. A tip for increased productivity is to measure the length you need, cut one, and then have your helper cut the required number to that length. With most building codes, reinforcing rod is put on every second course but I put it on every course. The advantage of that is you are building upon a wall that is more solid, will be stronger, and the reinforcing rods are not expensive. If you include this in your quote it won’t affect your bottom line but will shorten the amount number of man hours spent on your project.

Assuming you will use one for each course, you will require one for the top of the first course, and one for the top of each course there after, excluding the last course. In other words when looking at the glass block panel or wall, every visible course will have reinforcing rod in it. So if your glass block panel or wall is ten courses high - it would have eight lengths of reinforcing rod in it.

Always ensure that your reinforcing rod is handled carefully and doesn’t get kinked. This is very important, if you bend it you will have to cut out that section as it will exert pressure upon the glass block above it and mess up your wall. If the reinforcing rod is bent or has kinks, cut them out. If you have to cut your reinforcing rod to shorter lengths, do so. You can place your reinforcing rods on the wall in more than one piece, and sometimes you have to due to the length of the glass block panel or wall. In this case there must be overlap of the reinforcing rod by at least eight inches.

Mixing Glass Block Cement

You need to mix your cement now. As the cement sets fairly fast you won’t want to make more than you will need in the next forty minutes or so. As the glass block cement sets it becomes less workable, it gets lumpy, the glass blocks won’t sit right, and it doesn’t stick.

On your tarp have your five gallon mixing bucket, a second five gallon bucket about half full of water, your bag of glass block cement (called ‘mud’ by glass block installers and bricklayers), and your mixer.

When you mix your mud in the bucket you want it to be the right consistency from top to bottom. A common problem is that the mud will be alright at the top but as you go down the bucket when working, you will find that at the bottom and especially around the bottom edges, it will be hard as it hasn’t been mixed properly. If you do not have extra glass block cement with you, this wastage could cause you to have to go back to the supplier to get more cement. It also causes you to lose your rhythm when you are working.

Avoid this by adding a splash of water to your bucket before you begin mixing. Swish it around and get it over all the inside surfaces. Now add a small amount of water.

To mix the mud properly in a bucket you have to stand on the bucket. This may sound strange but if you don’t the bucket will spin around as you mix. But more than that, when you are standing on the bucket and your weight keeping it still, you have leverage to push your mixer down to the bottom and around the bottom edges to ensure that the mixing is thorough.

You have a splash of water in your bucket now and the sides have been swished. Your bag of glass block cement should be handled carefully, and you should be wearing your disposable rubber gloves.

If the glass block cement is handled without due care a cloud of very fine cement will spread out and you will end up breathing it. As it is cement and sets when moist, it will turn into cement in your lungs and nostrils. You’ll be prying cement boogers out of your nose all day so pay attention to what you are doing. You might want to have adequate ventilation or preferably be outside to mix.

You have added a small amount of glass block cement and mixed it to a slushy consistency. You should over water this step, as it will act as lubrication when you mix your batch of mud.

Now you want to fill maybe ¼ of the five gallon bucket with water. Next open your bag of glass block cement. The best way is to cut the corner with a knife to make a spout. Pick up the bag and pour cement in the bucket until it is about half full.

Now stand on the bucket and mix it. You might want to consider wearing safety glasses. If you get cement in your eye you will know it as it will burn you. The cement is a strong base (why you use vinegar, a mild acid, to clean your hands) and will burn just like acid in your eye will. You will have to flush your eye with fresh water and it will still be tearing up all day and you will have a red eye for several days after. You don't want look like a cry baby on the job. It happens and you have been warned!

As you mix your glass block cement, go up and down, and when you hit the bottom go around the edges. Step off and look at your mud. There is a good chance that if you aren’t experienced doing this it will be too wet or too dry. Add either more water or more glass block cement to the bucket and mix it again. This is why you make only half a bucket at a time.

  • Tip - to check the mud to see if it’s workable, scoop some up with your trowel. If it runs off it’s too wet. You should be able to scoop some up, give your trowel a shake, and turn it upside down and it won’t fall off. This move in itself is basic to glass block and bricklaying and you should perfect it before you even contemplate laying any glass block. Once your mud seems right, add a small amount more water and I mean just a few ounces to make it a bit looser. This is because in the first few minutes after mixing glass block cement takes a quick set. You have to counter this before it happens.

Take your bucket of mud to where you are going to install the glass block.

Tempering your Cement

Tempering is the act of making your glass block cement (aka mud) more workable. You should also have a small container of water (a drinking water bottle works well as you can cap it so if it spills you don’t make a mess) and a small container of dry cement (powder). This allows you to easily make adjustments to your mix on the spot without wasting time or labor. This is called tempering the mud. You have to be very careful when you temper you mud. Tempering glass block cement can only be done once, after that it will not retain the qualities that make it successful for setting glass blocks and being workable. Should you temper it and it gets too wet, you can add some dry cement (powder) to it to get the right consistency.

Best practice is to only temper once and after that throw it way. It won’t set properly and could shrink and crack after setting if it’s been tempered too much. Don't use mud that has been tempered and lost its workability, you will regret it.

The First Course

The first course is the most important course you will do. It supports all the weight of the blocks above. It has to be perfectly straight, perfectly level, and evenly spaced. It is the foundation for your whole window. A mistake in your fist course will be exaggerated in every following course until you have no choice but to tear it down and start again.

Brush your window sill off of dust. Place your spacers along the opening in roughly the right area (you will move them so it doesn’t have to be exact).

  • Tip: You will need to know how to gently flick your trowel to get your mud to come off and lay in a neat row. If you haven’t done this before you should commit some of the mud to practising this move. Most importantly never knock the side of your trowel on the glass blocks to knock the mud off. You will chip or crack your block, if not the first time, at some time. So it’s really important that you know how to do this.

Now that you have mastered or already know how to lay the mud from the trowel, lay a bed of mud along your opening from side to side. It is very important that your laid mud be of sufficient quantity that you can furrow it.

Furrowing

Furrowing is when you turn your trowel upside down (twist your hand to accomplish this) and place it at one end of the bed of mud and move it along the center line of the mud, pulling it up and down, flexing the tip of the trowel to create a valley in the middle, which will have furrows every ¼ inch or so. You should ensure that it doesn’t expose the base surface though so practice this if you aren’t familiar with this move. If you expose the base surface you could potentially have a leak down the road (more on this soon).

As you furrow your mud will be displaced and will slop over the edge. Clean this up by running your trowel along the length at an angle, to scoop it up. Place the excess either in an area where the furrowing requires a little more mud, or place it back in the bucket. Do this for both sides. It should look picture perfect after this step.

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Laying the First Course

You want the mud on the first course to set quick. After spreading the mud and furrowing, get your container of cement powder and (a smaller trowel in this container will aid you greatly) sprinkle it over the surface of your mud. This aids in it setting faster. Butter your first block on one side only (buttering is the act of swiping your mud that has been pre shaken on your trowel, so it will stick, onto the outside edge of your glass block. If you haven't done this before then practice until you are confident in your abilities). Do this on both sides.

Lay your glass block very gently down on the bed of mud, such that it is slightly above the spacer, and the end against the wall, which has no spacer (yet) is just a tad higher than the other end. Now you remember when you were snapping the tabs off your glass block so you could use them on the first course? There was one part of the spacer that was ¼ inch thick that you should have saved. Insert this little piece under the end of the glass block against the wall.

Use your rubber mallet to gently tap the block down to the spacers, and tap it in towards the wall. Don’t tap it too far into the wall or you might have to readjust it later, meaning that you will need more mud packed in against the wall, so best to stay a bit more than the ¼ inch out.

Do the same thing at the other end of your opening. Once that second black is in place you can lay the blocks from side to side. But don’t butter the blocks, just gently set them in place with no mud in between the blocks, just with mud under the base, not in the vertical joints.

The Horizontal Joints

These are the most important tips to learn if you want to lay glass block successfully. It goes against everything that a bricklayer would do and against common sense. I laid glass block for many years before I met an old pro who was willing to share his tricks with me. He was the fastest glass block installer I’ve ever seen and although I'm now retired, I have never seen anyone else using his trick. I have a few tricks of my own and they will be spread throughout this article, but this is by far the best.

The basic premise of bricklaying and block laying is that as the wall is built the brick or block absorbs the moisture from the cement and assists in the cements drying. It may not be apparent that this is the mechanism, you might think that the cement just dries, and it does to a degree, but any bricklayer knows that if his bricks are wet after its been raining, his wall will be a mess. The cement (called mud or mortar depending upon where you are) will drip out of the joints and run down the wall. Attempts to clean it up will result in often times permanent marks on the bricks. And the bricks will move in the wall. As the mortar becomes saturated by the excess of water in the bricks, the weight and pressure of the building materials above will distort the wall at any signs of weakness. This is why bricklayers cover their wall and their bricks when it rains or they go home when it looks like it might rain. Rain clouds are sometimes called beer clouds by bricklayers.

A similar process occurs when laying glass block. As the glass blocks are not porous they will absorb no water. So a similar situation happens as the wet wall situation described above. Although we are used to the cement setting in a bricklaying scenario, when using glass block the cement can take on additional qualities. The water can flow through the cement aided by gravity and the cement at the bottom of the glass block wall or panel will ooze out. As the cement is not drying, any additional weight on the wall by adding more glass blocks will compound this. The wall will bow out and eventually an inexperienced installer will have to tear it down. Not knowing how this process occurs, or better stated, how to defeat this process from affecting your work flow and your productivity, not to mention your self esteem, is critical to a successful job and career. One must throw away conventional wisdom and embrace a new style of glass block installations.

Lay the cement for your first course. Place the spacers on the blocks, attach the reinforcing rod, panel anchors, but don’t apply cement between the blocks themselves. If you have cement between the glass blocks you will get the seeping. You can’t get around it.

After you have placed your reinforcing on the blocks, get your small container of dry glass block cement (powder) and with your trowel place a sprinkle down in between each glass block. Also place a sprinkle where the glass blocks meet the wall on the cement there. Now sprinkle a bit on the tops of the blocks. The purpose of the dry cement is to aid in the cement setting quicker. You might think that it would weaken the wall, or provide a dry channel for water to leak through. Rest assured that as long as you don’t overdo it - it will not cause any problems. The water in the cement will seep into the powder and it will set. For the parts that are not set, assuming you haven’t over done it, they will become part of the vertical joint when it is filled.

I can state with confidence that the wall will not leak when constructed this way. I offer the home owner or building contractor the lifetime ‘no leak’ warranty. I know that it will set correctly as I’ve had occasion to take down glass block walls or panels I have done and they have been rock solid with no seams or faults that they fracture down or come loose when they are dismantled. Also I have never seen any powder in a glass block wall or panel that has required dismantling.

The reasons vary as to why a glass block wall or panel has to be torn down, but I am happy to give a few examples.

I always confirm with the building contractor or home owner as to the exact location that the glass block wall or panel is to be installed. Once the building contractor got it wrong and it was eight inches off. This required tearing it down, discarding the broken glass, and starting from scratch. I did not mind as I got paid for putting it up the first time (mistake was not mine), got paid for tearing it down (equal pay to installing it), and paid again to reinstall it.

I had one wealthy home owner who liked remodeling. I would install him a glass block window one year, and then next year he would come up with a new design. I ended up replacing the glass block window three times, and of course I was happy to do so!

There have been times I’ve tried to enable a helper who has stuck with me for a long time to learn the trade. Unfortunately I have had to tear down some of their work.

So I have confidence that this method will not cause any leaks or weaknesses. Also I have never had to fix even one leaky window, but I have fixed several leaks by another installer.

The vertical joints will be covered later; this is to ensure that the work flow is as straightforward as possible.

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Important Joint Tip

The joint has to be fully filled with mortar. When you furrow it or fill a joint, there shouldn’t be any air spaces. These are easily visible by looking at the inside edges of the glass block. Looking into the glass block you can see the cement through the edges. If there are any furrows they will always be visible to anyone who knows where to look. It is also possible that water could pool here and if there is a cold climate (i.e. sub zero) it could fracture the glass block. The furrowing is done to allow the glass block to seat smoothly and without undue effort to force the block into place.

When you are doing the vertical joints (described later) you have to ensure that there are no air pockets or voids in the cement. If you see one of these issues whether it be a vertical or horizontal joint, you should immediately fix it. If you let it dry you will not be able to fix it and the integrity of the glass block panel could be compromised. It is easy to fix when the cement is still wet (not set). Use your tuck pointer and push it into the joint space to compress the glass block cement. Once the void or cavity is filled continue using your tuck pointer to fill the joint in.

Back to Your Window Panel

You have laid your first course in cement and have placed spacers on the joints. You need to look at where the glass block panel, that is the plane of the window, meets the edges of the opening. Before starting the work, you would talk with the home owner or building contractor and find out if they want it flush on one side, or set back a certain distance.

If it is flush with one side it is easy to straight line. You pick your level based on the size of the window opening. Your level should be long enough to go from outside of the opening on one side, to the outside of the opening on the other side. As your level is being used as straight edge only for this alignment, a piece of wood such as a 2×4 could be used, as long as you have looked down the wood from the end to ensure it is not warped. The idea is that if the level (or wood) is held firmly against the out side of the opening, the glass block can be gently tapped into alignment.

If your glass block panel is not flush with the outside surface, you should have used your level (or can do so now) to mark a line on each where the glass block panel will align. This mark provides you a visual reference point so you can look at your glass block panel and easily see if it’s going according to plan. You have two things to watch out for. One is a lean on one or both of the sides, and the other is a bulge in the middle.

If your glass block panel is not flush with the outside surface, use a level or straight edge that is slightly less in length than the glass block panel is in width. This allows you to manoeuvre the level within the opening width, along the length of the If your glass block panel is not flush with the outside surface panel, without the opening sides interfering with your straight edging. A good practice is to have a small circular saw on hand and several 2×4’s of various lengths, and cut one down to the size you need. If my opening was 56 and ¼ inches wide I would cut a section of 2×4 to 55 inches long, this allows me to straight edge the entire length of the glass block panel. Always ensure that your 2×4 is not warped and always use the 2 inch side of it for straight edging as it will generally not warp in that direction. Check it each day for straightness as if the 2×4 was left outside rain could cause it to warp overnight.

This should be done on the bottom of the glass block. Often times the window sill will not be flat and the blocks will have an obvious tilt in one direction. This is where your shims come in handy. The cedar shake shims can be broken or cut to the required thickness, and good plastic shims work equally well.

For the tilted blocks, place two shims under the base per block, one at each corner so the glass block won’t become uneven. It’s very important to ensure that the shim is long enough to be pulled out after the cement has set. That’s where the cedar shake shims have an advantage as they are longer and won’t disappear underneath the glass block. Insert your shims under the tilted blocks until they are in a straight line and in alignment with your level placed across the opening at the tops of the glass blocks.

You will observe that the glass block cement under the blocks has been sucked back or gaps have appeared. You have to get some glass block cement on your trowel and use your tuck pointer to swipe mud from your trowel filling the cavity underneath the glass blocks. You might also have to swipe some into the vertical joints at each end of the glass block panel.

Double check your first course of glass block by placing the eight inch level crossways on the middle of each glass block. This is just fine tuning and ensures that you are good to go.

Now that your first course is sitting perfect, you should ensure that it becomes set firm before you go much further. Place a small amount of the dry glass block cement powder in each vertical joint between the glass blocks. It will fall down and settle on the wet mud below. Also place a sprinkle on the wet cement on each end of the glass block panel.

If you have some experience under your belt you can do a second course, but for the purposes of ensuring that the first course sets well and provides a solid foundation for the rest of the glass block panel, a break is recommended at this point. Taking a 20 minute break allows the glass block cement to take a set. Taking a set means that it forms a bond. Continued work will create movement, and even minute vibration will stop the glass block cement from setting properly. Should your first course go fine and you do a second course, it would be advised that you take a break then.

Taking breaks to allow the glass block cement to set actually increases your productivity as a solid foundation can be worked upon more. I generally take a break at the first course. After that I might add two to four more courses before taking my next 'setting' break. Your glass block panel will tell you when a break is required. When it starts getting harder to maintain the glass block panel plane without bulging or tapping blacks into place – it’s time for a break. I’ve often said that you work for an hour and a half and then take a half hour break. Although this is not always necessary, and sometimes you are under pressure with time constraints, it is a good rule of thumb to follow. It's all part of the job and you have to get used to it. However if you are slow at the installations, your breaks will be delayed. The work determines when you break, which is at what point it requires setting.

The Second Course

After the first course, each course goes faster. That is why it is so important to ensure the first course is solid and correct.

At this point you have either taken a break and come back, or are ready to carry on. Assuming you have taken a break, you would check your wall with the level and reposition shims if required, and tuck point as required.

Your spacers should be in place and you will be ready to reinforce and anchor your glass block panel. First you will attach your panel. If you are attaching it now, bend it at a 90 degree sharp angle about seven and a half inches from the end. This ensures that it won’t stick up above the next glass block. Screw it in according to the instructions in the Panel Anchoring part of this article. If needed top up the glass block cement at each end prior to attaching the panel anchors.

Now you should cut a length of reinforcing rod to go from side to side of the glass block. Leave it an inch short on each side so it won’t interfere with your spacers. For instance if your width is 56 and ¼ inches - cut your reinforcing rod at 53 to 54 inches in length. If you cut one and instruct your helper to make the required amount, it will aid in your productivity.

Place your reinforcing rod on your glass block panel. Ensure it sits flat or cut out any part that sticks up. Especially look at the cut ends for signs of uplifting. Fix where required. Again check your glass block panel for alignment. Sprinkle a small amount of dry glass block cement (powder) on the top surface of the glass blocks.

You will have spacers in between your glass blocks but will require one at each end. Use one that has been made the same as the ones used on the bottom course. Place one in the joint at each end. This is why your panel anchor needs a sharp bend. If the bend is not sharp the spacers will not sit right and your end blocks will not sit right. The process of working with glass block requires perfection in every aspect of your work, but it’s not hard if you pay attention to the details when you are working, and it will come naturally as your skills progress.

Temper your glass block cement if required, or make new mud if it’s beyond repair. Spread your mud along the tops of the glass blocks and furrow it. Remove off the excess by scooping it off with your trowel.

Butter a glass block on both edges of one side and insert at the outside of your glass block panel. Do the same for the other side. Now gently lay the glass blocks in the middle and gently tap them onto the spacers with your rubber mallet.

Use your level or straight edge to check that your glass block panel is aligned with the outside wall. If it is not going to be aligned with the outside wall, check it for plumb (dead vertical) with your level and by looking at the vertical line you marked on the wall.

  • Tip - there will be cases where the wall you are installing your glass blocks in will not be plumb. If this is the case, and you are laying your glass blocks to be flush with the outside surface, do not plumb them according to the bubble. You can straight edge them to the outside dimensions, and use your level vertically to straight edge them but don’t go for dead plumb. Each case and each window ill be different and it is up to you to be adaptable and read the wall to know where to have the plane of your glass block panel be. It might require that your first course be off level, so if you have to over ride anything in this article, do so, but know why you are doing it.

Your second course should now be finished and spacers in place. You have sprinkled some dry glass block cement (powder) into the crevasses between the glass blocks. Top up the joints at the outside edge with glass block cement and sprinkle some dry glass block cement powder on them to firm them up.

The Next Courses

Attach your next set of panel anchors (or bend them down if they are pre installed. Place your reinforcing rod on the glass block panel. Sprinkle some dry glass block powder on the top of your panel, and do the next course. Repeat this for the following course.

  • Note - the glass block panel can not be built too high as it’s not set enough yet. Should you keep going you will reach a point where the wall will get out of control. You will need to stop then and preferably before then. As a rule of thumb I stop every four courses for twenty minutes to half an hour. During this time the glass block panel hardens and you can either refresh or clean up, move materials, etc.

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Note that in addition to the spacers, the panel anchor is correctly attached to the wall, and the reinforcing rod is in place.

Cleaning the Glass Blocks as You Work

It is very important that you take care to not get your blocks messy with cement. After each course has been completed you should run the tip of your trowel between the joints to dig them out. Even better is one of the twist off tabs from the spacers. This will dig in deeper but as it’s plastic it won’t scratch the glass. Always beware when metal touches glass.

It is important to keep in mind that the glass block cement is not the finished surface that will be visible to the eye. Once dry a coat of finish grout will be applied. The finish grout is water proof (the cement is not) and the finish grout is a finer consistency and provides the beautiful finished look.

But all your care and attention to detail will be lost and your hours of manpower increased significantly if you aren’t careful in keeping the blocks clean.

Wipe off any mess on your glass blocks as you go using a sponge. As the sponge gets wet it just makes the mess worse so use different edges of it to prolong the longevity of your sponge until it requires washing and drying (meaning it will be out of action until dry again).

Take your breaks and when you come back look at your glass blocks. Are they firm and has the glass block cement on the surface of them dried to appoint where your finger will wipe it off? If so wipe them gently with a dry sponge. A dry sponge will remove the glass block cement.

  • Tip - never use a wet sponge as not only will you make a mess but you are introducing water to something you are trying to keep dry. This is a common mistake that tilers make and can lead to you having to take your wall down and start over, having to tinker with a wall that is shifting, or just prolonging the cleaning process significantly.

As your sponge gets wet, which happens fairly quickly, toss it away and use a new dry one. If your sponge is even mildly damp, it will leave a sheen of glass block cement that will not be visible until it dries. This can usually be removed with another sponging. Get your helper to clean your sponges a you go.

If necessary and you see dry snots (little chunks of cement on the glass block wall) gently remove them with the edge of a plastic spacer tab. In the grooves around the edges of the glass block there is a fine line where the glass block cement will set. Until the glass block cement completely dries, it is not that visible, but once dry it sticks right out. The best way to deal with that is to get into the practice of using your 000 grade steel wool to clean the grooves around the edges of the glass block.

  • Note - this only applies to Pittsburg-Corning glass blocks as Weck glass blocks do not have this groove. I would speculate that the designer of the blocks had not installed any or he would have eliminated this fine groove.

A final buff with a clean rag and your blocks will look great. Do this after every break and before starting work again. If the cement or finishing grout dries hard it could take you hours to clean and the finished product may not look as good, either as the joints are messy, or you neglected to tweak any blocks that may have moved out of alignment with the glass block plane. Remember you are only as good as your worst job!

After Taking a Break

When your blocks are clean and reasonably firm you can continue doing more courses. Your vertical joints still haven’t been done yet and this will be addressed shortly.

Depending upon how long it takes you to do your glass block window, i.e. whether it can be done in a few hours, or there will be a long break of an hour or more in the work flow, determines when you will fill the vertical joints. At this point we will assume that your window is small enough to do in a few hours and that you are ready to do the last course.

The Last Course

This one is a bit harder and like the first course, it is very important that it be done correctly, both from a visual perspective and a construction perspective. It requires using a new technique to place the glass blocks in. As you can’t place them in from above (as you are at the top), you have to slide them in, and the tabs on the spacers will probably be in the way.

If you have been placing panel anchors and reinforcing rod on every course (when most building codes require they only be put in on every second course) you can skip them on this course. Unless there are concerns that you have to address, such as high security as it’s a glass block window at a bank or jewellery store, leave the panel anchors and reinforcing rod off on this course. This course will be a little harder and as your glass block panel already exceeds the building code you can concentrate your energy on ensuring the top course is perfect.

Your spacers will require modifying. The tabs on the side will have to be twisted off so that they don’t obstruct the placement of the block. An additional problem you will face is that the spacers might slide out if you aren’t careful.

Start the course like the other courses – sprinkle some dry glass block cement (powder) in the joints of the previous course, but this time don’t spread any on top of the glass blocks. You will also only be spreading the mud for one block at a time. You’ll want to start at one end first, so get some glass block cement on your trowel, give it the practised flick so that you can hold the trowel upside down without the glass block cement falling off, and slide your trowel along the far side of the end block. This will form a ridge of glass block cement there, and then you do the same for the side near you. Use your trowel to smooth it out and make it almost flat. I say almost flat as you should have it sloped downwards on the side facing you.

Now the first two and the last block on this course will be the hardest. Pick up a glass block, and butter the one side that will go against the wall as usual. Then carefully turn the block so that you can smear glass block cement on the bottom surface of the block. When you have it covered with glass block cement, angle the smeared mud so that the far side has less and the side nearest to you has more.

Your block is now buttered on the side facing the wall, and on the bottom, at the reverse angle of the mud on the glass block in the window. You have one more tricky step ahead of you yet with this block. You have to smear mud across the top surface of this block. It doesn’t have to be a lot but it has to be smeared on so that when you use your tuck pointer to fill in the last joint, there is something there for it to stick against, otherwise it won’t fill the cavity properly and you could get leaks. Your block will be getting heavy in your hand but you are ready to place it in the wall now.

You will be doing a new move for this course. Turn your trowel upside down, so your hand is under the blade, and while holding your glass block you have to slide it into the corner of the last course of your window opening. And you have to try not to knock your spacers off of the glass block. If you get lucky you might have enough room to leave the tabs of the spacers on, but this is something you would try dry first. If you knock your spacer off just keep going with placing the block. Once in place slide your trowel out.

Your block might not be sitting pretty but you can break some spacers apart into ¼ inch thick pieces and insert them at each corner of the block. You have probably figured out that you will need access to both sides of the window by now, so you might have to work on placing the spacers in the right position by going inside and outside. You’ll also have to place a spacer on each side where the glass block meets the wall. Once you have it in place, even if it’s a bit messy, repeat this procedure on the other side.

Congratulations you have just placed two very hard blocks in the glass block window. Just a few more glass blocks to go.

Place glass block cement on the next block in on the first side you did and use the same procedure as described above, keeping your vertical joints empty of glass block cement. This time you only have to smear glass block cement on the bottom of the block in your hand. Use your trowel to smooth it out and make it almost flat, sloped downwards on the side facing towards you. Use your trowel to place it the same as you did the end blocks. If the spacers move fix them.

Repeat this again alternating sides (so that they can settle somewhat) until you come to the last block.

The last block is another hard one but if you have been able to get this far you should be able to do the last one too. Use your trowel to smooth it out and make it almost flat. I say almost flat as you should have it sloped downwards on the side facing you cement on the wall, same as every other block. Smear mud on the bottom of the block in your hand and angle it towards you. Use your trowel and your hand to slide it in place. This one is a little harder as you have to let go of the block when you are placing it. As you set it, move your hand from the top, to the upper side of it facing you. Insert it carefully. If you push it in too far it could fall over the far ridge of the glass block you are trying to set it on. If that happens place your spacers on the side facing you, then go outside and insert your trowel underneath the block and gently lift it into place while inserting spacers to support it.

Stand back for a minute and look at your glass block window. It’s not done yet but most of the hard work is over. Look at the last row and see how it lines up. It’s probably a little wobbly so be careful adjusting it. You could even wait twenty minutes or so for it to firm up – it will be easier to tweak into place then.

At this point you should have all your glass blocks laid and the glass block panel should be on the right plane – i.e. it should be flat and flush with all sides, or recessed the correct amount and looking good. If for some reason you see something that doesn’t look good, you will have to fix it before it sets completely. This next step will give you some tricks on how to adjust a glass block window while you are building it or after you have finished, assuming it hasn’t completely set.

Adjusting a Glass Block Window as it Sets

Apart from the gentle tapping of blocks that is done as you lay each course or the pressure and tapping of the level to align a course, there are a few tricks that you can do when the glass block window doesn’t want to behave. This could be due to a tilted surface that the first course is laid on, a spacer slipping out, some one knocking the wall, vibration from a third party, etc. You or your helper might also notice a block or two that have a corner sticking out slightly.

This sometimes happens if the reinforcing rod is not perfectly straight and flat. It might look alright and you’d think that the weight above it would make it negligible, but as vibrations from you working on the wall hit this spot, it will shift the blocks. It can be frustrating so ensure that your reinforcing rod is flat and has no kinks before you use it. Take care transporting your reinforcing rod so it doesn’t get bent.

Regardless of the reason you still have to deal with fixing it. Your rubber mallet, your tuck pointer, and your trowel are you best friends now.

You have a limited amount of time when you can adjust a glass block that is setting. You can’t exert much pressure when your glass block is fresh set, and you can’t do anything when it has set, but in that flux time in between you are able to make some minor adjustments.

  • A glass block whose spacer has broken or fallen out - this glass block will be tilted down towards the direction that the missing spacer is. If the spacer broke and the plastic piece is not visible, you can insert your trowel underneath the glass block on the affected corner and list it up, while sliding in a piece of a spacer, or a wedge is need be. As you are actually lifting a block up, you can only do this when it is no more than two courses down. So when you are working keep an eye out for this potential problem.
  • The wall has a bulge or some of the glass blocks have ‘lipped’ - this happens to some degree on most every glass block project. It’s not hard to deal with as long as you fix it at the right point in time. When it if fresh laid or a few courses along, the glass block cement will still have some movement in it as it hasn’t fully set yet. Using your level, gently tap on the glass blocks with your rubber mallet. Now, it’s very important that you know how to tap with a rubber mallet. If you do it on the center of the glass block you risk cracking the block. You have to tap the block on the edge of the block where it has some strength. If your wall is a bit sloppy (it moves fairly freely as it hasn’t set enough) you should just place your level over the offending glass blocks and push them into place. This won’t weaken your wall or cause spacers to break or shift out of position.

You should be taking breaks every four courses to allow for the glass blocks to set. As you work you might notice that one or more of your blocks down below, where they have mostly set, could be out of alignment for some reason. You can use your rubber mallet to knock these blocks into alignment even when partially set. This will usually work for two to four hours after setting the glass blocks, depending upon the temperature and humidity where you are working.

If the glass block has set and there is glass block that is noticeably sticking out, you have little option but to remove it and replace with another glass block. You can try to hide it with you fill the joints with the finish grout later, but if this doesn’t work you have no option but to replace it.

The Vertical Joints

Your vertical joints have been left out to aid in your work flow to lessen problems with the water in the glass block cement flowing down and oozing out of your glass block panel. Knowing when to do the vertical joints is important. Definitely don’t do them when your horizontal joints are still fluid, they need to be mostly dry.

After you have taken a break to allow the glass blocks to dry is a good time to look at your glass blocks to see how they are setting and how they are sitting. I wouldn’t fill the vertical joints of the glass blocks on the first course until I had taken a break to let it set, and then laid a few more courses and let that set.

  • Tip - a good rule of thumb is to only do the vertical joints of work that has at least set over the course of work and two breaks. The important thing here is the timing being related to setting breaks. If you have checked and rechecked your blocks for proper alignment and the glass blocks from two breaks ago are good and the glass block cement mostly set, you can do the vertical joints on these blocks. However due to the glass blocks from your most recent work still being in a fresher state (not enough setting time yet), you should not do the vertical joints that are in the immediate course under your fresh work.
  • Procedure - your plastic grout bags are your best friend now. You should ALWAYS with a fresh batch of mud, not a tempered down batch. A tempered down batch of glass block cement will have inconsistencies in its texture that will become caught in the grout bag and cause you problems. If you try to use tempered down old mud you will find out the hard way and time is money in this trade, so use new mud. That said the new batch should be slightly looser (wetter) than the consistency you were laying the blocks with, but not too wet.

To check your glass block cement’s consistency for use in the vertical joints, you first have to look at your grout bag. It is hoped that you have been able to find the plastic grout bags, even if you have had to import them internationally. A regular grout bag that you commonly find just doesn’t have the proper qualities to allow for the smooth flow and ease of squeezing. You can check this out if you like, and can compare it to an alternative home made plastic grout bag I will talk about shortly, but the plastic material is superior and pretty much required to properly do the vertical joints.

If you have the correct grout bag it will look like a witch’s hat and the pointy end will not have an opening. You will cut the opening yourself and the size of it is important. Laid flat I use a utility knife or pair of scissors to cut the end. I cut it that so laid flat the width is about 3/8’ s of an inch. This allows you to cut a fraction more off if it’s too tight, becomes damaged, or your glass block cement is too tight (becomes too hard).

Before you use your grout bag runs some water through it and swish it around so the glass block cement will not stick. As the Canadian saying goes, the cement should flow through the grout bag “like shit through a goose”. When your cement is freshly made, and don’t do too big a batch at a time, place some in the grout bag and see if you can squeeze and it come through the end like toothpaste coming out of a tube. This is the consistency you want. If it’s too loose it will just mess up your glass blocks and flow out the other side of the joint. If it’s too tight it will require a lot of force to squeeze out of the grout bag and it may well damage the opening of the grout bag. Considering how hard these are to get you want to be careful with them. If the consistency is not right (you should be squeezing it back into the bucket while testing) tip your grout bag upside down and empty it back in the bucket. Always rinse your grout bag after each test an after each use.

When your consistency is correct you will know it. Go to your lowest course first and squeeze the grout bag to get the glass block cement in the vertical joint.

  • Tip - your joint has to be solid from side to side. Look at the inside wall of the glass block to see how your glass block cement is filling the vertical joint. It should be totally filled with no wavy lines where there is air. This will occur so how you deal with it is important.

Start filling your joint at the bottom and watch as it fills. Try to squirt it as far over to the other side of the glass block as you can. Keep going up and filling it. Obviously you will have to do it from the other side too, but for now stay on only the one side and go across the course filling all the vertical joints. Once this course is done, squirt a little more into the top of each joint to ensure that the glass block cement does not sag or contract during setting there and cause a cavity that might leak or hold water. Do the next course only if the horizontal joints at the top are solid. If the horizontal joints above where you are working are still fresh, you should not do them for risk of making the horizontal joints absorbing moisture and the glass block panel losing some temporary structural integrity.

When you have finished doing all the vertical joints on that side, you have to go outside and do the same thing. It should be easier as it will probably require less glass block cement. Check your glass block cement and you can temper it if it is getting too hard.

You will probably find that as you do the vertical joints (and this applies to both sides) that the glass block cement will harden and will not be as workable. When this occurs don’t force it but dump the glass block cement from your grout bag and back into your bucket and temper it so that it will be good again. Remember that glass block cement takes a fast initial set so it might be good for five minutes but will quickly require a bit more water and mixing (tempering).

As you do your vertical joints watch for cavities forming in the glass block cement. When you see this aim your grout bag at it and try to fill it with pressure. It if doesn’t fill, as the cement might be lumpy or some other reason, use your tuck pointer to pack the joint and then refill it from the grout bag. Even after the glass block panel is finished you can use your tuck pointer in this way to pack and fix vertical joints with cavities.

Once you get proficient with the consistency of the glass block cement and using your grout bag you will find that the work of filling the vertical joints will go very fast. Don’t underestimate the amount of glass block cement you will use. It will be about equal to the amount used for the horizontal joints.

  • Cleaning the vertical joints as you go - if you are following good work and safety practices, you should be wearing disposable rubber gloves (latex style) and safety glasses. You should also have a clean sponge handy. As you finish a joint use your finger to wipe it and flick the excess back into your bucket. When you have done this to all the vertical joints give them a light brush with the clean sponge. A light brush is all they require until they set.

Getting Back to Work

If you still are working on your glass block panel, you can resume laying the horizontal courses. If you are caught up and your glass blocks have dried, and all the glass blocks are in correct placement and alignment, you can fill the vertical joints on the top courses, and finally fill the top horizontal joint, the same as you did the vertical joints.

Your Glass Block Panel is in Place

When you have all the glass blocks laid, and all the vertical joints, and the top joint grouted on both sides, its time to let it dry before applying the finish grout. It’s also time to clean it up.

Cleaning your Glass Blocks After Filling the Joints

This has to be done at the end of every day, or when your glass block panel has dried, or is almost dry – what ever comes first.

The first thing you have to do when the glass block has set, or is sufficiently set, or you are going home and want to clean the blocks that are set or sufficiently set, is to twist the plastic tabs on the spacers off.

You will see that the glass block cement will be in a blob where the spacer was. If it’s still soft use the plastic spacer tab to wipe the glass block cement out of the joint. The advantage of using the plastic spacer tab is that it won’t scratch the glass block. If it’s too hard use the tip of your trowel to clean these spots.

Always try using the plastic spacer tab to clean your joints and to remove any snots before anything else. If there is glass block cement anywhere else than the joints that requires removing, do not use your trowel. Use the 000 grade steel wool that you have on hand.

When you look at your glass blocks, there are steps to cleaning it prior to applying the finishing grout. These are:

  • 1. Remove the spacer tabs and remove excess glass block cement from the joints either with the plastic spacer tab or your trowel.
  • 2. Remove any snots (spots of dried glass block cement) on your glass blocks by either using the plastic spacer tab (so you don’t scratch the glass block), or using the 000 grade steel wool.
  • 3. At this point your glass blocks will probably have a splash marks and dust on both sides. This is easy to clean. Get your supply of dry sponges ready. A common mistake that tilers and people inexperienced in glass block make is to attempt cleaning them with a wet sponge. There is nothing you can do to glass block that will create you more man hours of work than to do this. Always use a dry sponge. If the glass block cement has dried sufficiently you will be able to wipe it off by rubbing your finger on it. This is when you clean your glass blocks. Use your dry sponge and wipe all the glass block surfaces up and down, and across. After doing the main surfaces of the glass block, pay particular attention to wiping the joints. As your sponges become damp, rotate them in your hand so you have a dry section to wipe on the wall. If your sponge becomes damp and you continue using it, you will notice that you are just making a mess. Always rotate your sponges so that you are always using a dry one. Have an adequate supply of dry sponges on hand at all times.
  • 4. The joints have to be recessed enough so that there is room for your finish grout to be applied on top of the glass block cement. When you apply the finish grout later, any small bump or spacer sticking out will show up and cause you problems. Now is the time to ensure all your joints are snot free and have no spacers sticking out. If a spacer is sticking out, you can usually use your trowel to cut the plastic and remove the piece that protrudes. Also remove any shims that have been used to keep the glass blocks tilted correctly.
  • 5. Pay particular attention to the outside edges of your glass block panel. Ensure that it is recessed sufficiently for you to either place finish grout or to caulk it when you are finished.
  • 6. Go over your wall one more time with a dry sponge. Your glass blocks should be looking good at this point. They should be perfectly set, all aligned with each other and with the plane of the glass block panel. They should all be clean and shiny.

The Finish Grout

This will be the last step in the construction of your glass block window. Finish grout is also known as tile grout so look for or ask for that if you are at a Supplier or construction warehouse.

Finish grout is made by several manufacturers depending upon where you are and where you shop. If you are in the USA I recommend using the ‘Polyblend’ brand as it has good qualities for use on glass blocks, such as easy to squeeze through the grout bag, it sticks nice, it’s easy to smooth for your finished joint, and it’s available in a good variety of colors. I have used other brands and some are not very good and I rate all against the Polyblend brand as to how effective and workable they are.

If you are experimenting with a new brand of finish grout make sure you keep your receipt if you have more than one bag so you can exchange or return it if it doesn’t work out for you. They vary a lot in quality and application to this use.

Choosing a Color

If you are using Polyblend the most popular color choice is ‘Antique White’ which is used in upwards of 95% of all glass block windows and walls. There is also a standard white but it’s very bright. There is a good selection of colors to choose from so if you are an installer and you are meeting with potential customers, carry a color chart around with you. Everyone will want a copy of any brochures you have on hand, so to save paper, and your continued energy sourcing more brochures, it is best to tell anyone requesting one that it is your only copy. If you have a website you can refer them to that and have the color chart on on of your webpages. No one ever returns brochures, even if they say they will, it's human nature so don't get upset, get a website.

It’s important to know that the color you see on the paper chart might be different to the finished color of the grout, as two different mediums are being compared – glossy paper and cement.

Polyblend Grout Color Chart

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Try to steer customers away from dark colors. If they choose a dark color you should charge a significant fee on top of your quote for that. I once did a glass block wall that had Charcoal Black as the finish grout color. It made the largest mess I’ve ever had to clean up on any job. Every surface everywhere had black dust on it and it was almost impossible to clean off. The white dust by comparison is almost invisible. I spent about four additional hours every day cleaning the glass blocks. I also had to throw away all my sponges as they wouldn’t come clean, and my hands, even though I was wearing disposable latex gloves, were black for a good two weeks and the black stayed in my fingerprints and under my nails for a lot longer. If some one wants you to use a dark color, you should be aware of how that will affect your hours of labor, and your personal appearance.

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Glass block shower with black grout. Go for the light colors in grout.

Grouting

We will assume that you are using Polyblend Antique White for this part of the job. You won’t need a large quantity of finish grout as a little bit goes a long way. All you are really doing is placing a skim coat on top of the glass block joints. It is the finish grout that is waterproof so you want to ensure that the joint is fully filled.

Your glass block window or wall should be complete and the joints dry before you grout. It is good practice to work late (if you have to) and come back next day to finish grout and clean up. You should never apply finish grout if you will be laying more block on the all later, as it will get messy. This is always the last step in the construction of your glass block project.

Before you start double check the joints in your wall for snots or spacers sticking out. You can run your finger or your trowel along the joints to ensure they are clean of any impediments.

You should use a small bucket or plastic container to mix your finish grout. As you only use a small amount at one time, you mix this by hand. Just place small amount in your container, add a little water, and mix it with your smaller trowel. If you have a small rectangular trowel it will work even better, but what ever you have will do the job.

Don’t mix too much at a time as it sets very fast and can only be lightly tempered once. When it is nice and creamy with a toothpaste like consistency, it is ready to use.

You should be using a grout bag just for the purpose of finish grout. This grout bag should have a smaller opening, about ¼ inch cut off the tip of the bag when it’s laid flat.

Place some of the finish grout in your grout bag. Care should be taken when using a grout bag, now or when you are filling the joints, that when you put mud in your bag that your trowel does not cut the side of the bag.

Leave the joint around the opening of the glass block window until last. With the other joints you can get a movement going where you squirt the finish grout onto the joint and do all the joints going up, or all of them going side to side, and then switch methods.

Always do your vertical joints going up and push the stream of finish grout that is coming out of the grout bag into the joint so that it sticks. When doing the horizontal joints also push the grout into the joint.

Depending upon the size of your window or wall determines how much you will grout at once. This comes down to how the finish grout is setting. If it gets too hard it won’t be easy to work to a nice finish, and if too loose it will get messy. If your finish grout falls off the joint, it is either too dry or you haven’t pushed it into the joint hard enough.

After you have done a few courses you will need to make them look pretty. If I was doing a four foot by four foot glass block window I would do all the vertical joints on one side and then make them look nice. Then I would do the horizontal joints and make them look nice. Finally I would do the outside edges (assuming they won’t be getting caulked).

When the outside edges are done, you should run your trowel down them to ensure they have a nice crisp line where they meet the wall. Pay attention to the corners as they tend to accumulate finish grout. Once you have done this, sponge it so it looks good.

Finishing Your Joint

When your finish grout is at the point of being of a hard toothpaste consistency, run your finger (in a disposable latex glove to protect your finger from the chemicals and provide maximum sensitivity) along the joint pushing the finish grout in and squeezing the excess off the joint so it falls off. You should have a hand underneath to catch the excess to keep the job clean. It is important that you are consistent in how much pressure you put on your finger, and how deeply it recesses the joint. Ideally you want it slightly concave but full.

After you have run your finger down the joints, and before you fill any more, use a dry sponge to clean the joints. The glass blocks will start looking really nice by now. If you find you are smearing the joint, it is still too wet to work. But do give it a light wipe on each side of the joint to clean the glass block. The finish grout sets extremely hard and sets very well. Any mess on your blocks has to be cleaned as you go.

We will assume that at this point you have done the inside. Go to the other side of the glass block panel and do it the same way.

After this is finished you have to go back to the first side you completed. Your work is not over yet, as you have to dry sponge it one more time. Concentrate your efforts on the glass block and try not to smudge or mark the joints. Pay particular attention to the fine line around the edges of the glass block as it tends to trap cement and grout.

One more step – get your 000 grade steel wool and polish the lass blocks. Avoid the joints as you will trap grout in the steel wool which will scratch the glass block. When you are finished give it a final light buff with a dry sponge.

Stand back and admire your work for a few minutes. Note where you had difficulties, and where you had to apply adjustments. Assess how effective your adjustments were. If you see something at this point that doesn’t look right, you should seriously consider knocking that glass block out and replacing it, hard as that task may seem right now. Your reputation and quality of work are only as good as the worst glass block you lay. Always keep that in mind.

Caulking

I recommend caulking all exterior windows all the time. Leaks are not good for your reputation.

If the glass block window panel is going to be mounted externally, that is exposed to the weather, you should caulk the edges instead of finish grouting them This involves a little more time but not a lot. You have to wait for the finish grout to set before you can caulk, so going for lunch or taking a break is a good way to pass the time.

Now that the finish grout has hardened you can caulk it. Your caulk should match the color of the finish grout. You won’t get an exact match but it’s not that important as long as it’s close. There are two main types of caulk you can use for this.

The easiest is water cleanable caulk. With this one you can apply it (similar to grouting but you are using a caulking gun) to the edges, and then wipe it with a damp sponge to clean off the excess. It’s quick to apply and quick to clean.

However if this is a commercial job or you are in an area that experiences heavy rain you should use a silicone caulk. Most glass block suppliers, tile suppliers, and masonry suppliers have expensive caulks you can buy. A standard silicone caulk (of the correct color) will do the job just as efficiently. These are applies the same as the water cleanable caulk, but they are a lot harder to clean. The silicone tends to stick to everything and nothing will remove it.

  • Tip – use isopropyl alcohol (or similar) of as high a strength as you can acquire, and dampen a sponge with it. You will find that a sponge dampened with isopropyl alcohol will clean silicone caulk as easy as water will clean the other caulk.

Cleaning up

Assuming you are satisfied, gather your tools and start carting everything back to your vehicle. Clean up your mixing area. A good practice to get into is to use the boxes the glass block came in to pile garbage into. You should also be flattening the excess boxes as you go. The idea is that you keep on top of mess and can make a quick graceful exit from the job site with a minimum of extra work.

The last part to clean is under the windows. Your drop sheet will have proved its worth many times over as you untape it from the wall, roll it up with al the mess inside it, and throw it in a garbage bag. Use a broom and dustpan to remove any debris that got under your drop sheet, and finally vacuum the area, especially where the floor meets the wall. Your customer will appreciate your attention to cleaning up, and the care you have shown by using drop sheets. Providing this attention and respect to the customer’s home or job site will increase the number of referrals you receive in the future.

Using Expansion Strips

This section deals with the use of expansion strips. These are required around the glass block where they meet the wall. They are always used in concrete openings due to expansion and contraction of the concrete walls.

They are also required in earth quake prone areas such as California. The theory behind expansion strips in earthquake prone areas is that when the structure is shaken, the wall will move within the opening, but not break. I have not had one of my glass block windows go through a major quake yet but when this type of installation is done I inform the customer that the impact of a quake on this new building code is not yet known and there could be damage. I speculate that the window could shift in the opening, requiring it to be removed and rebuilt. Further speculation is that this is the intent of the design, with damage being preferable over cost of life. I still warranty my windows as being leak proof, barring a major earth quake. Expansion strips come in lengths of 24” and are available in Slimline and regular 4” widths.

The process of installing the glass blocks is similar except that you won’t be buttering your glass blocks at each end. You will cut a piece of the expansion strip at eight inches long. Place this between the wall and the glass block at each end. Ensue it fits as well as possible. Do this every course on both sides and add your panel anchors and reinforcing rod every course like before. One difference is that your window opening will be a little bit too tight.

When you calculated the dimensions for the previous window opening, you used the formula of ((multiples of eight inches)+1/4 inch).

Make this opening slightly bigger so use this formula to calculate the dimensions of the glass block opening ((multiples of eight inches)+3/8’s of an inch) and you will find it fits well.

It’s important to have the right size opening as if it’s too loose the blocks will tilt somewhere, and if it’s too tight your glass block window could bulge out one way or the other. Also your glass block window will not firm up as well when you are working on it, so you have to charge slightly more for the installation. Once you’ve done a few they become easy but still add another two hours onto a four foot by four foot window.

Additionally they have to be silicone caulked to ensure they are water tight and the silicone caulk also adds to the integrity of the window.

Your Finished Glass Block Window

Take a few photos of your project from different angles and with good lighting. Do this on every job and over time you will assemble a collection that you can display on your website, and you can carry a photo album with you when you do quotes. A good photo is worth a lot more than a thousand words when you are doing construction work. It is your income and your reputation.

We’ll now progress to more advanced glass block projects.

Next Project – A Curved Window

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A glass block window that is curved requires more skill as there will be challenges on this project that you will not encounter on a standard glass block panel. A glass block window that is curved can’t be straight lined and has a tendency to bow outwards in the direction of the curve. Additionally the joints will be different sizes on each side, requiring some advanced skills in maintaining consistent sized joints that are vertically aligned, and the same size as the other joints. This section will cover the additional skill sets and tools you require to ensure you complete a beautiful glass block window that you can be proud of.

This section will not go into as much detail as the previous window, as you should have those basic skills and techniques down by now. This section will build upon your skill set and apply them to a harder project. We will also cover the single biggest trick to ensure your curved window is successful.

The Layout

At this point you will have your drop sheets down on both sides, your tools nearby, and your materials stacked up and ready to go.

The first step is to ensure the inside surface of the window opening is securely flashed so that there is no wood to cement contact.

Before you even think about making cement you have to check the dimensions of the glass block opening. The height is done the same as in the previous straight window example, but the length will be gauged differently. The important side is the inside of the curve, or the side that is most visible. For instance if the window is in a bathroom that is viewed from inside and it curves out, the inside horizontal distance is the important measurement. This is calculated as in the previous example – i.e. – in increments of eight inches plus the ¼ inch for the final joint.

But the outside won’t have ¼ inch joints; they will be wider, so the outside glass block dimensions are not as important. However that does not mean that the angle of the window can be so great that the outside joints are huge. A glass block curved window can only be built with a certain radius to afford the Manufacturers Warranty and to comply with your local building codes. These should be consulted and the more stringent restriction used. As a rough guide, an exterior joint shouldn’t be any wider than ¾’s of an inch. At a size greater than this there could be problems with the appearance of the joint and the drying of the grout. On a curved glass block window you will also use more glass block cement.

Assuming that you have estimated this job correctly and the dimensions comply with the Manufacturers Warranty and building codes, you are ready to layout the first course and ensure that it actually does fit correctly. Should the opening be out of plumb or level you will have an even tougher time so be sure to emphasise this prior to the window opening being built.

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You’ll need a construction pencil handy and place your glass blocks on the opening dry. Start from one end and proceed around the opening. Use a spacer with the plastic tab on one side broken off to check that the inside glass block joint is always ¼ inch. If the curve is gradual enough that you don’t have to remove the plastic tab on the spacer, great, but this doesn’t happen often. When you have gone from side to side and adjusted the glass blocks to form a nice curve, it’s time to step back and look at the big picture. How do the blocks look on the other side? Use your level (you might need a six or eight foot level if it’s a big window) to check that the outside openings are plumb, or note how far out of plumb they are. If they are ¼ inch out of plumb at both ends, you will have to check every block to see if it meets the top opening ¼ inch off. If it doesn’t you can’t adjust the glass block without it looking strange, so you would build your wall as it should be, and the opening on top may not align, but no one will ever notice. The joints in the glass block create a grid and on a curved wall it’s very important that the grid look perfect. This is the key to success on a curved wall.

To fine tune the joints on the outside and to ensure they all match in size, use a block of wood that is cut to a taper of approximately the width of your outside joint. As you go around the wall, find where they fit on your block of wood. Adjust your blocks so that they all have a ¼ inch inside joint and a consistent width outside joint. Cut your block of wood to the required width and use that as a measurement as you go to check the joint thicknesses.

When you have verified that the first course looks good, use your construction pencil to mark both sides of each joint, on the inside and the outside of the glass blocks. Also run your pencil along the base of the blocks to mark how far in they will be recessed.

If your glass block window is flush with the outside or recessed in a little, it won’t make much difference for your work and ease of laying the glass block.

You are now ready to mix some glass block cement up. It is very important that this course be rock solid before you start on the second course. The previous example of a straight window required the first course to be firm, but this curved window requires that the first course be set solid.

If it’s a long length of window, you might want to consider adding panel anchors from the bottom surface of the opening going vertically up the joint. This will aid in your first course having a lot of strength and not being set off the base of the window by an earth quake or impact in the future. If you do this, consider adding one at least every three glass blocks and have it bent at a sharp 90 degrees with about 7 inches under the block, and 7 inches going vertically up. This ensures that the panel anchor won’t interfere with or extend past the immediate block.

Go around the window, starting from one end laying the glass blocks. You will use the spacers as you did in the last project to support the glass block underneath. Look at the pencil marks for your joints and the line that you drew to confirm that the placement is correct and you are not drifting off of target. When you get to the second last block, do the end block first. As the end block is buttered with glass block cement and needs to be firm against the wall, you do it first so that the last glass block that you lay will just slip into place. Now step back and look at the curve. Does it look round? Are the blocks level across the top? Very carefully and with no expense to time, ensure that each block is laid at the right spot that the joints are the correct size, and each block is level and plumb.

It can’t be stressed enough that the first course be perfect. When you are satisfied that it is good, pour a sprinkle of glass block cement down each joint and at the ends to assist them in drying. Make sure that your glass blocks are reasonably clean.

Now you have to go have a break for an half an hour to let the first course set. If you continue doing glass block windows and showers you will realize that despite all the hard work, there are points throughout the day and depending upon where you are at with your glass block job, that you have to take a break. If you let the glass blocks tell you when to take a break and not do so at a certain time, your time and productivity will be more easily managed.

  • Tip – in glass block it is not speed that increases productivity, but knowledge of how your glass block cement sets under different conditions. This is the biggest tip here.

After you have had a half hour break, come back and look at the blocks. If any have tilted, you will need to reset them. Assuming it isn’t extremely hot you should be able to adjust them by using your tuck pointer to compress the glass block cement under any of the blocks.

Mix some more glass block cement and when the blocks are where they ought to be, you can top up the end joints, and fill the cross joints. If this is only a small window you can skip this step, but if it’s a big window you will want all the strength you can get, especially to apply your next big trick. On this example we will take the worst case scenario and assume that your window is large.

If your window is large, after filling the cross joints you will want to take another half hour break to let them set. If it’s cold or rainy consider having a small heater on hand and tarping the opening in so that you can heat it to aid in drying.

You will have been at least two hours on the job by now and have only one course in. If it’s any consolation, it will go a lot faster now. The bigger the opening, the more important it is that the first course be solid. If you only have a small opening, you can skip by this previous step if you feel sufficiently experienced.

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8×8 vent installed in a glass block window, just install it like a block, ensuring that it opens correctly in the proper direction, hinged at the top on the outside so that rain drips off and not in.

Supporting the Glass Block Window from Bowing

This is the big trick that was coming to aid you in completing your glass block window in a minimum of time and effort. To perform this it was essential to have the first course set properly. Given enough experience you will know when to bend the rules and which way to bend them, but for now let that first course set solid.

For this part of the project you will require a straight 2×4 for each glass block row that goes up vertically. Each one should be at least as long as the glass block window opening is high. You will also require a selection of cedar shake for shims, or alternatively, you can make your own wedges (whatever works best for your budget or skills).

Cut each 2×4 so it is about 1/8 inch too short for the opening. Now place the base of your first 2×4 by the outside edge of your first glass block at one end. It helps when doing this to have a helper or another person. With one person holding the 2×4 at the base of the glass block, with the skinny side by the glass block, you will use a ladder and hold the top of the 2×4 in the approximate right place. Use a hammer to drive your wedge between the 2×4 and the upper surface of the window opening. When it is in place, use your level to check it is plumb and aligned straight (not tilting off to one side). Tap the 2×4 with your hammer to get the correct placement. Keep doing this with every block. This is why you had to have a first course that was set properly, and the solid first course will now allow you a good amount of speed in your glass block installation. Done correctly this technique, although costing you time at the beginning of the glass block project, will allow you to complete it faster.

You should now be looking at your first course with 2×4 uprights on the outside of every block that are aligned with the plane of the window. You can now attach your panel anchors on each end.

Your spacers will probably require the plastic tab being removed on one side, and of course that side would be on the outside, where the glass blocks are supported by the 2×4’s. Your reinforcing rod (required every second course in most building codes) obviously won’t bend around a curved wall. But you can use your wire cutter to cut off a section in between each cross piece. This will now allow your reinforcing rod to bend. As you are doing this every course, which is especially important on a curved glass block window to ensure it stays in place and doesn’t get away from you, you are meeting (or exceeding) the building code requirements. Care must be taken when bending the reinforcing rod that it stays flat. You don’t want any kinks messing you up on a curved glass block window.

Now that your panel anchors are on, your spacers in place, and the reinforcing rod cut to size and in place, you are ready to mix some glass block cement. First you will want to sprinkle some dry glass block cement on the surface of the glass blocks. This will aid in the drying of the next course, which greatly increases the stability of the glass block window as you build, and your productivity.

When your glass block cement is ready, butter the glass block for one end and lay it, then do the glass block at the other end. The rest of the blocks will now go in quite fast. If you have done everything right, you should be able to place the glass blocks in place as fast as you can pick them up.

When the second course is finished, check it out to make sure it looks alright from inside and outside, and that your 2×4’s haven’t shifted, and if everything is alright, you can proceed to the next course.

When you have two fresh courses laid you should asses how stable the glass block window is. Look at your work and make sure nothing has shifted. If everything looks alright you can keep going.

At the fourth freshly laid course you should take a break and let the glass blocks set. If you push it too far you risk the weight of the glass blocks and the vibration of your efforts, to knock one of the 2×4’s out of place. If this happens you are going to have big problems so you always have to be respectful of your work flow and pay attention to detail and break times.

If the Window Gets Away From You

After your break you will assess how ell the wall is going. If you need to adjust any blocks or any of the 2×4’s do so. Double check the outside of the glass block window to make 100% sure it isn’t leaning outwards. If this is happening you will have to try and adjust the wall. This situation does happen sometimes so you have to know how to deal with it.

Individual blocks can be tapped with the rubber mallet but if you have an entire row, or several rows leaning out, you will have to move them all at once. You can do this by placing your level (or a straight piece of wood) against the row you want moved, and exerting a push against it. This should not be an impact like a rubber mallet, but you pushing your body weight against the row that is leaning out. The row of glass block should shift, but you have to be very careful as the rows next to it might also move, or a glass block could shift and a corner stick out off of the spacer. You have to realize that if this happens, there is a possibility it could get away from you and you have to tear down and redo a few course. That is why you make sure the first course is solid and take sufficient breaks and long enough breaks. If you try to hurry you will mess up the glass block project.

Continuing with Your Curved Glass Block Window

At this point you will have several courses of glass block in your wall. It’s a good idea to look at the lower course and see if the horizontal joints are dry. If they are you should mix some glass block cement and fill the two lower glass block course vertical joints. Don’t do the top two courses as they won’t be dry enough yet. Filling the glass blocks vertical joints aids in this windows setting and strength. As you are adding weight to a curved window, you want it to set fast and strong so nothing shifts. If you neglect to do the vertical joints, you put your glass block window at risk of shifting as you go higher. If it should shift, the courses that are filled in would stay solid. So you are effectively reducing the amount of tear down you would have to do in a worst case scenario.

When you have finished filling the vertical joints of the glass block on the lower courses, you can proceed installing more glass block.

  • Tip - one thing that is very important with curved glass block windows, is making sure that the exterior, or outwards facing side, has the vertical joints recessed in a bit from the edge of the block. It’s easy to build them up when you are finished but hard to chip them back without breaking a glass block.

The Last Course

Make sure you take a break before doing this one. It will be hard and you don’t want to accidently knock any of the glass blocks below this course off or knock your 2×4’s out if the glass block window is fresh still.

You should wait until the glass blocks up to the last course have fully dried. If this means coming back next day, so be it. The reason is that you will have to remove the 2×4’s to place the last course.

If your glass blocks are set, you can remove your 2×4’s. when you do this you will want to check all your joints for glass blocks or spacers that might have moved. This is also your last chance if something looks wrong and requires tearing down. Although I keep raising the threat of tearing down work, I have never had to tear down a curved glass block window. Taking care to follow the procedures I’ve outlined, and taking breaks when needed, combined with your due diligence and attention to detail, should enable you to complete a curved glass block wall with out problem.

Set your last course of glass block using the same method as you did with the straight glass block window. Always use your level not your eye to make sure everything is aligned.

When the last course is in , you should look over your wall again, and then fill any vertical joints that have set. You won’t be able to fill the vertical joints on the top course yet, but you can also clean the lower blocks. In other words although you can’t fully cement the top course of glass blocks, there is no shortage of other work to do. Consider leaving the filling of the vertical joints of the top course until the next day. It will be solid and will progress a lot faster then. If only a few courses are getting the vertical joints done the next day, you should be able to finish grout them too, if you exercise caution and care.

Finishing the Outside

The inside of the curved glass block window proceeds the same as in the first example of a straight window. The outside is similar, but as mentioned above care must be taken that the filling of the outside joints does not let cement protrude past the edge of the glass.

  • Tip - your finger won’t work for the outside joints due to their thickness, so use a dry sponge to rub the joints. When rubbing the outside joints with a sponge always use upward movements. One thing you have to watch for, even if you are experienced, is the tendency for the glass block cement to sag down and form a belly in the joint. Not only can this cause a cavity or void in the glass block cement, but it could protrude out and require you to chip it away or grind it out later.

Assuming all went well you are ready to finish grout your glass block window. Make sure you have good light when you do this. The inside will go quickly. On the outside take care when finish grouting to get a nice even surface on the joints, and ensure they are all consistent. It can be helpful to do it once lightly (it’ll set fat on dry glass block cement) and then give it a second coat.

Even as you are packing up, keep looking for any spots on the outside that catch your eye and touch them up if needed. Obviously you will clean up your glass blocks and your work site as described in the straight glass block window.

Don’t forget to take some photos of it from both sides. This glass block window will be a major selling point for your skills down the road. Congratulate yourself on another successful job.

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We’ll now progress to a free standing wall which will require new skills.

Building a Free Standing Glass Block Wall

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A free standing wall is used in showers and as a room divider. They can be straight, curved, or have a few corners in them. Corner blocks are made to accommodate 90 degree and 45 degree corners. In showers it is desired that the glass block wall enclose the shower to contain the spray. A free standing wall can be one of the hardest type of glass block projects you will do, but if you understand the dynamics of the glass block building process, and know a few tricks, the job will proceed quickly and will look great.

Prior to unloading any materials you should measure the dimensions and ensure they are correct for the spacing of your glass blocks. If there are any issues you will have to talk with the home owner or building contractor and either make them aware that there could be a visual problem before you start installing the glass blocks, or give them time to fix the problem, even if it means that you come back on another day.

At this point we will assume that the dimensions are correct. Bring in your materials and arrange the drop sheets around the area you will be working. If the foundation is raised, you can use painters tape to keep the drop sheet in place. If it is going to be built on the floor, place your drop sheets so they have some slack and can be tape to the first course of glass block after it has been completed.

Set your blocks dry upon the ground or foundation, you won’t need any spacers underneath them for this test layout. But as you lay them out, starting from the wall, place spacers in the top to ensure your test layout will be accurate. When finished look at how the glass blocks are aligned. Does this look straight in comparison to the foundation or other linear features? If a slight move will align it better you should do so, assuming that it will not present any new visual or dimensional issues. If any doubt exists or you want to confirm that you can proceed, call the home owner or building contractor over and show them what you are doing and why.

If you are ready to go, trace around the glass blocks with a pencil on both sides so that you can see where you will be laying the glass blocks. Mark where the joints start and end on the inside and outside of the glass block wall.

A free standing glass block wall should be anchored on every course on the one side where it meets the wall, which should be reinforced structurally where it meets the glass block to take any stress. If it is a shower you never know if some one will be getting amorous against the glass block wall and it should be able to take some thumping and force. For this reason you should also anchor it to the floor or foundation surface. Hopefully this will be tile or cement as that will provide good support. Use a concrete drill bit for a concrete foundation. If there is tile, you should confirm before you come to the job if the tile is drill-able. Some tile is but ceramic tile isn’t. If it isn’t drill-able, request that the tiler cut or leave some openings in his tile for you to drill through. Proper co-ordination and planning will ensure good results and will build confidence in your abilities with the home owner or building contractor.

Bend and cut your panel anchors so that 7 inches is underneath the glass block and 7 inches sticks up vertically within the joint. This length will ensure that the panel anchor doesn’t protrude out past the glass block in any direction to interfere with any of the other glass blocks. Drill these in every three courses at least and have one every glass block in the last two course. Building codes do not require this but common sense dictates it. You only have one surface to anchor your glass block wall to, so make sure it doesn’t shift if some one pushes against it hard.

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Mix your glass block cement and place your spacers where the joints are. There should be vapor barrier if the glass block will meet wood.

The block against the wall should be buttered with glass block cement so the joint is full. Changes to glass block building code in California now require that there be an expansion strip where the glass block meets the wall. In my opinion an expansion strip here weakens the wall and this joint should be cement. The expansions strips are designed for a concrete wall that expands or contracts, and recent building code changes in California that require expansion strips around windows are to allow the glass block window to move within the opening and not break or cause damage. However a glass block window is held in place on four sides. Your shower or meeting room wall is only anchored on one wall. If there is an earthquake it will move if there is an expansion strip in there and it will either crack along one of the courses or along the bottom joint underneath the first course of glass block. This is really a tough call and you should discuss it with your home owner or building contractor. I would recommend that if you build it with expansion strips that you write on their invoice that you are not responsible for damage caused by movement where the expansion strips are used in the construction of the glass block wall.

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Assuming you will be using a cement joint against the wall you will butter it and lay it in place. Use spacers to support it and keep it the correct ¼ inch distance out from the wall. Continue along your course until you have completed it. Add the spacers on top of the course of glass block. Now align your blocks by level at the base of the wall. If your wall is curved check that the radius or curve looks right and the joints inside and out are consistent.

Use your 8 inch level across the tops of each glass block crosswise to ensure they are sitting flat. Place a sprinkle of dry glass block cement (powder) down each joint to assist in drying, and trim any excess glass block cement from around the base of the glass blocks.

Let your first course of glass block dry for half an hour so it becomes solid. As in the curved window, you will want your first course set so you can proceed at a good pace with a minimum of fuss. When you come back from break recheck the alignment of the glass blocks and double check they are level. You can use your tuck pointer to compress the glass block cement under the block to raise it on one side, or your rubber mallet to realign a block if needed.

When this course has set you can start on your second course. The big difference when building a glass block free standing wall is that there is no opening to use to align your glass block as you go, and it is different from a curved glass block window as you have no braces for it to lean against. So patience is required to ensure that the glass blocks do not lean, or list at the end, creating an ever larger joint as it goes up. The best tip for this kind of glass block installation is to use panel anchors and reinforcing every course, and ensure they sit flat, and to check your wall with the level every course. If your wall gets away from you the best thing to do is take a break. After a break when it has partially set, it will take an adjustment better. If the problem is serious you will have to tear down the glass blocks that have gone out of alignment.

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Using Your Level

On a glass block wall you will have to use your level every course to ensure it is plumb and straight lined. There is a technique for this that every bricklayer will already know.

Assuming that your wall is straight, you would plumb the blocks on one side of your glass blocks near the wall. Then you would go to the end of your wall and plumb the outside end of your wall. You may have an end cap here or an end block. Regardless what you have you will plumb this plane first. After that you will plumb the glass block on the end. If any blocks are out of alignment, a tap from the rubber mallet on the other side, while the level is held opposite to brace the wall, will kick the glass block into alignment. There is no substitute for experience here so go slow until you learn this.

Always plumb your glass block wall at the same spot every time. Always do the same side every time, and as you go, you will only plumb one side of the wall. If it starts leaning you will place your level against it (on the side it’s leaning towards) and gently apply pressure to it, and place shims in the joints where required.

After you have both ends of the glass block wall plumb, place your level length wise along the course that you have just laid, so that the level touches both points that were plumbed. Where you level is, is the line that the glass blocks need to be in alignment with. Tap them gently with the rubber mallet on their base to nudge them into correct position.

You should also be watching your glass block wall for any bulges. These bulges are easy to find even if they are minor, if you use you level to compare the line it goes along from side to side, up and down, or diagonally, and look for where the glass block are away from the level, or the level rocks on a bulge, If you have a bulge tap if from the opposite side with the rubber mallet while keeping your side firm with the level. You only want the glass blocks that you are tapping to move.

Take a break every four courses; if your wall is wobbly you will want to break more often. If your wall is wobbly your glass block cement is either too loose (too wet) or is not being given adequate time to set.

When you reach the top course, take care to ensure that the glass block wall is still plumb and level in all directions. Let it dry, overnight if possible, and then remove your plastic spacer tabs. Take out any shims that you have had to use and clean your glass blocks and finish grout them.

Don’t forget to take your photo of the finished work.

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Glass Block Wall with a Corner

You will often get requests to build glass block showers that are enclosed, that have a corner in them to catch the shower splash. You would do your layout and construction the same as above, but the difference is in how you plumb your wall. As you go upwards in courses, plumb your first glass block from the wall, then do your corner block on both sides (far side first). From here you should straight line the first section from the wall to the corner.

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Then plumb your block on the end, and then plumb the last block on the inside. Straight line this section of the glass block. You will now have to check the first side. It can get a bit trickier with corners in your glass block wall as you are applying pressure and taps in directions that are opposing. Just go slow and your confidence will increase the more courses you do. Remember that the condition and workability of the glass block cement is the key to any successful job. If you run into problems you are either going too fast or your glass block cement is not the right consistency.

Curved Walls

Now you are getting into the hardest type of glass block wall to build. However if you have made it this far you should have the basic knowledge and the tips to allow you to finish this. A curved glass block wall is the slowest to build and adequate time should be allowed to complete it. Your labor estimate should reflect the amount of skill and time that will be required to build this glass block wall.

Do the first course the same as the above examples. When you are placing the spacers on the top of the glass blocks, you might have to remove the plastic tab on the spacers to allow the glass block to sit properly. Hopefully you won’t have to do this, as you will be able to go faster, but we’ll assume the worst case scenario for this last project.

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The first course needs to be perfect.

The main difference with this type of wall is that you can’t straight line it, and you won’t have any 2×4’s to brace it. On occasion you will get a job where you can use 2×4’s as in the curved glass block window example, but this is rare. Assuming you have some experience, or a lot of patience, you should be able to complete this job correctly.

After each course, place your spacers on top before plumbing. You will have to use your level to plumb each row of glass block. Use your rubber mallet gently as the wall will be more susceptible to movement, and your tuck pointer to compress glass block cement under any block that requires a boost. Keep a supply of shims handy as you could use quite a few in this wall. When you place shims, always put one on each side of the glass block, and keep them short. This allows you to plumb up the center of each block without hitting the shims. You can also use masking tape or painters tape to assist in holding the blocks in place as you work. Don't expect it to do much more than just stop them from getting away from you as you ready the wall for the next course.

When you are done, clean your blocks and finish grout as usual.

Replacing Glass Blocks

This can be tricky if the block are old and is always messy. There are many reasons that glass block get broken. Vandalism is the most common reason to replace glass blocks. But people drive cars into them on occasion by accident, and I’ve replaced glass blocks that have been used as target practice also.

I once kept getting called to a bad district of a nearby city to replace the glass blocks in a building where they kept getting shot out. After the third time I did repairs, the owner requested I tear down the wall and replace them with the solid bullet proof glass block. With these glass blocks the bullet actually bounces back. I never had to replace them again.

You will require another set of tools for removing the glass blocks. You’ll need a good hammer, a few chisels, a grinder with spare masonry blades, and a metal blade to cut reinforcing rod. You’ll also need heavy duty drop sheets to catch broken glass, safety glasses, safety gloves, long sleeve pants and shirt, and a first aid kit. As one side of the glass block wall is usually inside, you will have to tape disposable plastic drop sheets on the inside to stop the spread of dust.

You have to warn the home owner or building contractor that they should ensure their possessions are covered with plastic drops sheets and that you will do your best to control dust, but can’t be held responsible for any dust damage. Be sure to tell them of the precautions you take, and that you will clean up your immediate work area, but that if an accident happens and the dust barrier gets breached, it is a risk they will have to bear. The only time I’ve had a dust barrier fail is because I used poor quality tape and I then assumed the responsibility. You should tape your dust barrier on both sides to the ceiling, floor, and walls with good quality painters tape. You have to be conscious of where glass will fall, and in what direction debris from the grinder will go.

Getting the Glass Blocks Out

Getting them out is not that hard, its cleaning the cement out of the joints that is hard. To remove the glass blocks - and at this time you should have all your safety equipment on, drop sheets down, and dust variers up – tap the glass block in the center with the blunt end of your hammer. It will usually crack into large pieces that can be picked out while wearing thick safety gloves. There will be lots of small thin glass shards so exercise caution. If they are scattered around the glass block window, as usually happens with vandalism, you can take them all out at once.

If a vehicle has backed into a glass block window, they will probably be shattered in a row. If the damage is more then a few blocks along a course, you should consider taking out a few and replacing them, then doing the remainder. The main consideration is that if all the glass blocks are taken out, will the window crack along another joint if you take out too many at one time. This has to be assessed on a case by case basis but if in doubt take it slow.

When you have removed the damaged glass blocks, you will have to remove the cement around the openings. This is the hard part as cement gets harder as it gets older. If you have a 20 year old glass block window, the cement will be very hard and the glass block could be brittle from sunlight, street vibration, impacts, earth quakes, etc. The problem is that in removing the cement you don’t want to break any more glass blocks. This is not as easy as it sounds. One slip with the hammer or chisel and you have another block to take out.

If it’s relatively new construction (within the last 10 years) the cement will probably come out all right. Use your chisel (you should have several sizes) and ensure that when you are removing the cement that you never place the chisel where the glass meets the cement. Always place it in from the joint and angle your chisel inwards, so the force of the impact will stay in the cement. Once the cement chips away you can work on the remainder of the cement. The reinforcing rod will cause trouble. Assuming you have the cement partially chipped out on each side of the opening, the problem will now be the reinforcing rod and/or a panel anchor if the broken glass block is near the wall. For this you will need to use a grinder. Make sure you are wearing a dust mask and eye protection. Ear protection is advised also as you will be close to the grinder blade.

You have to cut the steel as close to the next glass block as possible. Remember that the opening doesn’t have to be perfectly clean, but just has to allow a glass block to be placed in and sit straight and plumb in alignment with the other glass blocks. When the steel has been cut, the rest of the cement will probably come out in one piece. You have to do this on either the top or bottom depending upon where the reinforcing rod is (or both if it’s built by me).

After you have gone around all the blocks and removed as much as possible, you will have to clean around the outside edge of the glass block that are still in place. This is so that when you do your finish grout that there are no chunks sticking out that will mess up your joint or catch the eye.

Putting the New Glass Block In

Test the opening size first by placing your glass block in the opening dry. This is to ensure that it will fit properly. If there are pieces of steel or chips of cement in the way you will have to remove them.

When your opening allows the easy insertion of a glass block, mix some glass block cement up and butter the opening on all four sides of the opening, on the inside and outside of the window. Also you will have to butter your glass block on all 4 sides. Try to do it lightly but cover all the surfaces that will be adhering to the cement. Use your trowel underneath the glass block like you did in the last course of a glass block window. Gently push it into place but don’t push it out the other side. Remove your towel.

Use shims to position the glass block in place with the correct joints all round. Use your tuck pointer to push glass block cement into the joint and fill it completely. This will dry fairly quickly as it’s surrounded by dry cement so ensure it is in alignment with the wall by checking it with the level. Place your level over the window where the new glass block is and use your level vertically and horizontally to check alignment with the plane of the window.

When you have replaced all your glass blocks, you can remove the shims, starting with the first one you replaced and going sequentially. When all the shims have been removed, fill any holes where the shims came out with glass block cement. Now use a dry sponge to clean the glass blocks.

As long as the glass blocks look clean you can apply the finish grout now also. You don’t have to wait as you did in the new construction projects as this is already surrounded by dry cement and the fresh cement will dry quickly. After your finish grout you should clean the glass blocks with a dry sponge. Let it set while you start cleaning up, and then come back to the glass blocks and use your 000 grade steel wool to clean any tough spots and along the refine ridges ta the sides of the glass block.

When you are finished give it a once over with a dry sponge to polish it. Go home and have a beer to get the grit out of your mouth.

Pittsburg-Corning Glass Block Brochure

  • not in its entirety.

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Estimating Materials

The last area I want to talk about is calculating the dimensions for any window opening or shower wall and coming up with a correct materials list. Below I will list examples from jobs I have done in the past. It is hoped that you will able to understand how this was calculated and to be able to adjust these numbers for whatever sized project you are doing.

If you are operating with a low budget and can’t or don’t want to supply materials, I have a way around supplying them. Your materials can be up to 40-50% of the total price of the job. So you don’t have to outlay that cash, and can operate as needed without capitol on a labor only basis, I’ve a good way to respond to potential customers that works well.

Tell your customer that you try to be competitive and offer the lowest price, and to do this, if you had to supply materials you would have to charge an additional 15%, and you would require a 40% deposit up front. Tell them that to save them money that you will provide them a complete materials list and they can just phone in their order and pay by credit card. And to clinch the deal let them know that you offer free delivery and will co-ordinate with the supplier to have the order ready for pick up the day of the job when they open. Now you do not require the funds or deposit to purchase materials, and the customer feels comfortable placing the order as they are in control, and saving money!

Estimating Example

Once you have your dimensions for the glass block project you are doing, you will know how many blocks up and across there are.

For this example we will cover basic materials for a window opening that is 8 glass blocks long and 6 glass blocks high. This would be 48 8×8 glass blocks.

As there are 6 courses in the wall you and assuming you will be using panel anchors and reinforcing rod on every course, you would need 8 panel anchors and 22 feet of reinforcing rod.

How did I come about this number? There are six courses going up. To place a panel anchor on every course, you will need one on the first course, one on the second course, one on the third course, and one on the fifth course (although you may elect to omit this one when you are on the job due to difficulty laying the last course). So you have four panel anchors for each side, and as you have two sides you would need eight panel anchors.

For the reinforcing rod calculation, it will go by the length of each course times the number of course you will be installing. Each course will be 64 inches long and there will be four courses you will be using it on (although you may elect to omit this one when you are on the job due to difficulty laying the last course). 64 inches divided by 12 (to get the length in feet) is 5 feet four inches. 5 feet four inches times 4 (the number of courses) gives you 21 feet and 4 inches. I have rounded this to 22 feet of reinforcing rod. However reinforcing rod generally only comes in specific lengths so you will have to acquire more then you need to ensure you have enough.

For the number of glass block spacers you will require, these usually come in bags of 25. Calculate the number you will require by using one spacer per block. So if you have 48 glass blocks you would need 48 spacers, or two bags of spacer. Some of these could be broken, and care must be taken when handling the bas to not damage the glass block spacers. I would recommend that you always have a few extra in case of breakage.

For glass block cement (and you should be using glass block cement not regular cement as glass block cement is white, and regular cement is grey and can be seen when looking at the sides of the installed glass blocks. Also glass block cement has specific properties that allow it to set better as glass blocks do not absorb any moisture. One bag of glass block cement should do 25 glass blocks assuming that the glass block installation will be straight. If it is a curved wall or window you will require more to fill the vertical joints. For this 48 glass block window you would require two bags of glass block cement.

You’ll also need finish grout, and as this varies depending upon the size of your wall and depth of your joints, ensure you have enough. Any extra can be used on other jobs, or returned if you buy the small packages of finish grout.

If you require expansions strips, which come in 24 inch lengths, measure the distance on both sides and along the top and add it together. In this example each vertical side is 48 inches long and it is 64 inches across the top. 48+48+64 = 160 inches total of expansion strips. As they come in 24 inch lengths, divide 160 by 24 to get 6.6. Obviously you will round this number up to ensure you have enough, so you would require 7 expansions strips.

You will also need some caulk so have a few tubes on hand. As it is hard to know how much finish grout and caulk you will use, if you are doing this for a living, the easy thing to do is to have an additional charge on top of your labor only quote to cover this expense.

Summary

For an 8 glass block by 6 glass block window your opening size should be 64 ¼ inches long by 48 ¼ inches high. If you are using expansion strips, make your opening 64 3/8 inches by 48 3/8 inches to allow for the slightly thicker expansion strips.

Your material list would be:

  • Forty eight 8×8 glass blocks
  • Two bags of spacers (50 spacers)
  • Two bags of glass block cement
  • Eight panel anchors
  • Minimum of 22 feet of reinforcing rod
  • Seven expansions strips (if being used)
  • Finish grout
  • Caulk – for the sides around the glass block opening if it’s an exterior window

Samples of Estimates

We will now look at some sample estimates. It is hope that you will be able to follow the methodology. Some will refer to specific building codes that may not have been covered, but as they are specific to your locale, you should not pay too much attention to them, and instead focus on the methodology.

Sample Estimate #1

Hi <customers first name>,

Thank you for calling me about your upcoming glass block project. I hope this will answer your questions and clarify things. I prefer to work on a labor only basis and request that you order your materials directly from <name removed> Glass. When you’re ready I’ll be happy to provide you with a complete materials list, and do free pickup and delivery of materials. I can supply materials if you wish but the cost would be slightly higher and a deposit required.

UPSTAIRS The 3’ x 7’ glass block panel wall. To install this panel you will need a framed opening of 3’ ½” x 7’ ½”. (This allows you a proper fit for the expansion strips which go on both sides and along the top. These are caulked and the final finish of tile grout will hide the strips and also covers the glass block cement. Panel anchors and reinforcing are required every course. All panels and windows are now required to be built this way. As this is exterior you can just use a framed opening with vapor barrier, no fire rating is required.)

The 8’ x 3’ horizontal panel requires an opening of 8’ ½” x 3’ ½”.

The 2’ x 7’ vertical wall panels. You have a couple of options here. If you frame them on four sides you would need a 2’ ½” x 7’ ½” opening. You could also just have them coming off of the corner stud, with an end cap on the exposed side, framing optional for the top. In this case you don’t have to get the critical dimension size as it’s not boxed in.

Installation of new window in bathroom where old one presently is. Fire rated windows require sheet metal channels on the openings(sheet metal wrapped back around the wall), covered with 5/8” thick sheetrock. Standard blocks are 45 minute rated. No matter what the rating all these types of windows require expansion strips on top and both sides, panel anchors and reinforcing every course, caulk on the expansion strips. I cover everything with tile grout for a nice beautiful finish. A 60 minute fire rated window requires a 60 minute block, these have slightly thicker glass walls on the blocks. Fire caulking is also required on the expansion strips. Lets hope they don’t require a 90 minute rating as these blocks are more expensive yet and require ¼” steel channels – I doubt they would require this, usually it’s only needed on the property line. A 45 or 60 minute window will fit easily into your opening and is the preferred installation. The dimensions the glass block window will take up is 64 1/2” x 56 ½ inch, and be sure to have the opening slightly larger to accommodate the 5/8” sheetrock on each side. This would make the framed opening 65 3/4” x 57 ¾”.

DOWNSTAIRS

The window with three 8” blocks above and below a 24” x 8” vent. Opening size would be 24 ½” x 24 ½” for the glass, plus you have to allow for the sheet metal and 5/8” drywall on four sides. The 4’ x 1’ window below the light well. You need a header above this. The opening size for the glass is 4’ ½” x 1’ ½”, assuming you can use 12” glass block. The problem here is that 12” block has no fire rating. SO – if the inspector says that you can do it you won’t need to sheet metal and drywall the opening. Or you could go to 6”x6” blocks or 8” x 8” blocks; these are available in 45 and 60 minute fire rating. (8×8 also in 90 minute).

The small openings under your windows. 12” block have no fire rating, so if fire rating is required then you would have to go to 6” or 8” block, sheet metal and 5/8” wrapped sheetrock. After talking to several people it comes to this: windows need to be fire rated, but small openings don’t, which means that you can put your 12” block into framing with vapor barrier, no sheet metal or drywall needed. We could then get by with a 3’ ¼ x 1’ ¼” opening (3’ ¼” x 2’ ¼” opening for the two course ones). There has to be wood between the glass block and the window. The optimal dimension is to have a half inch extra (ie. 3’ ½” x 1’ ½”), but I know a couple openings are already framed, and I could squeeze them in.

I know this is somewhat complicated, and you can call me any time for questions, clarifications, or changes. I’d like to see you able to use glass block wherever you wish and am happy to help you in any way I can.

Sincerely <your first name>

Sample Estimate #2

Hi <customers first name>,

I’ve been thinking about the windows you wish to install. What I’ve come to is this.

The 1’ x 3’ openings: These are questionable for your fire rating as we’re not using fire rated block, and they should have drywall around the openings to be fire rated. Finish inside the openings should be 12 3/8” x 36 3/8” – this is the opening size the glass block will take up.

The 2’ x 3’ openings: These should definitely have drywall around them, as well as expansion strips on sides and top. Panel anchors and reinforcing rod also. Opening size for these windows should be 24 ½” x 36 ½” to accommodate the drywall.

The small window downstairs - to be up to code it would require drywall on four sides, expansion strips, panel anchors, and reinforcing. I hope you are happy with the work we did, we definitely appreciate your prompt payment, and have tried to keep the labor price as low as I can (with two people working) to reflect this. Weather is a big factor this time of year - hard to work if it’s raining. Also it would be great if you could have several windows ready at the same time as I do have a $300 minimum charge.

I hope you’ve had a great holidays, and wish you a healthy, happy, prosperous new year!

Sincerely <your first name>

Sample Estimate #3

Hi <customers first name>

In regards to our prior conversations, I’ve put everything in writing for you.

Building code: We are working on the premise that this is a 45 minute fire rated window. The framed opening (with a header above), shall be lined with 5/8 inch sheetrock. I recommend the green waterproof type, although that is actually not required. The opening size within the sheet rock shall be exactly 32 ½” by 72 ½”, to accommodate the expansion strips that shall be on both sides and along the top. These shall be caulked inside and out. Panel anchors and reinforcing rod shall be on every course. Glass block cement shall be used for construction. Final finish will be with snow white polyblend tile grout, for a beautiful finish, even the caulking shall be grouted so everything looks the same.

Labor & materials would be $xxxx.00, payable upon completion.

The glass block used would be 8x8x4 decora 45 minute premier blocks.

Please call me about any questions, queries, scheduling, weather, etc.

Sincerely

<your first name>

Sample Estimate #4

Mr. <customers name>

RE: Installation of interior glass block window.

Construction of glass block set in masonry, panel anchors and reinforcing every course. Both sides and top to have expansion strips in place, caulked both sides, as per code. Final finish of poly bend tile grout, snow white is standard, unless other wise desired.

This window will have a 45 minute fire rating (probably not applicable as interior application).

Blocks are available in 3” and 4” thickness. The blueish one is Pittsburg-Corning “decora” pattern. The darker one is Weck, “nubio goldtone” pattern. The p-c blocks are about $5 each, the weck blocks run slightly higher, about $6-7.

Labor cost for installation is $xxx, payable upon satisfactory completion, materials extra.

When the home owner decides upon which type of block he/she desires, I shall give you a complete materials list, all you have to do is phone it in and pay, I provide free pickup and delivery.

Any questions or queries please don’t hesitate to call me.

Thank You

<your name>

Sample Estimate #4

Mr. <customers name> Re: 10 xxx St, City Name

I enjoyed meeting with you. Thank you for the opportunity to bid on your upcoming glass block project.

You have a choice of decora (wavy pattern), and icescapes (frosted pattern) for your shower. I shall drop off a sample of each block at your house on Friday mid-morning, one is 3” thickness, the other 4” thickness, but you’ll have to use the 4” thick ones for the shower. For your window I’m assuming we’re using 6x6x3”thick blocks. If that's incorrect please let me know.

The window shall be set in glass block cement, panel anchors and reinforcing every course, expansion strips on top and both sides, final finish of “snow-white” polyblend tile grout, unless other color is desired. The ideal opening size is 18 3/8” x 60 3/8”.

The shower walls will be set in glass block cement, panel anchors and reinforcing every course, extending up 96”. Final finish to be of “snow-white” polyblend tile grout, unless otherwise desired.

Estimated time for completion is four days.

The price, all inclusive, labor & materials, is $xxxx.– , payable upon completion.

Please call me anytime with any questions or queries, or to go over layout.

Thank you, <your name>

Sample Estimate #5

Hi <customers name>

This is the materials list for the two glass block openings. You can order it from xxxxxxxxx Glass Blocks, <phone number>, on 10th St. at xxxxxx Avenue. You can even do it over the phone, and I will pickup and deliver for you.

Quantity 61 Regent Glass Blocks (one extra) 3 bags of 4” Spacers 3 bags of glass block cement 26 panel anchors 1 – 10’ length of reinforcing rod 24 expansion strips 3 tubes of glass block cement

That’s it. It will take one day to put them in, and will finish grout and polish the next day.

Thanks, <your name>

Sample Estimate #6

Hi <customers name>,

45 minute fire rating don’t require angle iron or steel channels, panel anchors would be used to tie into the existing masonry. This is definitely the cheapest way to go. Blocks are about $5 each, and you save by not having to fabricate or install steel around the edges. Maximum panel size is 84 sq ft (Uniform Building Code) and you can go up to 12 feet between vertical supports. This doesn’t affect you as 12×8=96 sq ft. Might as well just assume you have to have vertical support every 10 feet (8×10=80 sq ft).

60 minute fire rating also doesn’t require steel angles or channels, just fire caulking on the expansion strips. 60 minute blocks are available for $11 each. Here maximum panel size is also 84 sq ft, and you have to have vertical support every 10 feet. This would be slightly more expensive.

90 minute fire rating only requires steel angles or channels. These blocks are available for $12.50 each (bulk price). It is my understanding that 90 minute fire rating (UBC) is needed if the wall is within 3 feet of the property line.

Whichever block you choose, the vue pattern would need to be ordered ahead of time to ensure adequate supply. Delivery time would be three to four weeks, something to keep in mind.

I hope this helps you – please call me any time for questions or clarifications.

Thanks, <your name>

Sample Estimate #7

Mr <customers name>,

To calculate dimensions for glass block openings:

Each block is 7 ¾ inches. The joint is ¼ inch. So we go across or up in increments of 8 inches, and then add 3/8 inch (once) to get the final measurement. For curved walls the measurement is done on the inside radius.

i.e. 8” x 15 blocks = 120” , then we add 3/8” to get 120 & 3/8”. The glass block panel would be 120 & 3/8” tall.

6”x8” and 4”x8” blocks are also available.

Panel Sizes:

Standard premiere blocks (45 minute fire rating) don’t require angle iron or steel channels. Blocks are about @$6-7 each. Maximum panel size is 250 sq. ft. (Uniform Building Code) and you can go up to 20 feet between vertical supports. This is for an interior non fire rated panel. So if you’re going to go 10 feet high (15 courses), you’d have to have a vertical support or post every 20 feet. (10’ x 20’ = 200 sq. ft.)

For fire rating maximum panel size is 84 sq ft (Uniform Building Code) and you can go only up to 12 feet between vertical supports. If you have a 10’height you’d have to have a vertical support every 8’. (10’ x 8’ + 80 sq. ft.)

60 minute fire rating blocks also doesn’t require steel angles or channels, max panel size of 84 sq ft, only 10’ between vertical supports. They are available for @$11 each. Installation is the same with the use of fire caulk.

Only 90 minute fire rating requires steel angles or channels. These blocks are available for @$12.50 each (bulk price from the supplier). These are for exterior walls within 3’ of the property lined.

Construction:

Glass block panels are built out of glass block cement, with panel anchors and reinforcing on every course. Expansion strips (caulked both sides) are required on both sides of the panel, and along the top. Panel anchors are also required along the top. Final finish is of polyblend tile grout, snow white is the standard color, but other choices are available by request. If using wood for framing and/or vertical supports, it should be sealed or sheet rocked prior to installation of glass block. Framing can be of wood, metal stud, or steel. The vertical support would preferably be of steel, but could be wood post. A door would require it be set in a steel frame (glass block is not structural). The outside dimensions would have to work for the glass block spacing. The height (top of steel frame) would be an increment of 8” exactly, and the width (outside dimension, side to side) would also have to be an increment of 8” exactly.

Costs of materials: (panel anchors, reinforcing, expansion strips, spacers, caulking, glass block cement, & tile grout) will add on @$x-$y per block. I don’t supply materials, but can provide a materials list, and it can be phoned in. I provide free delivery.

Glass block has excellent sound reducing properties, an interior wall will provide a quiet environment. Different patterns are available, from see through (Vue), to wavy (Decora), to LX Filter (cant see through). Patterns of different glass blocks can be incorporated into panels.

Sample Estimate #8

Hi <customers name>

Thanks for calling me about your upcoming glass block project. I hope I can answer all your questions to your satisfaction.

  1. 1) Price of decora vs. vue 60 minute blocks. Decora 60 are $ 10.80 each, Vue 60 are $12.15 each. To keep costs down for you I ask that you purchase materials yourself. I provide a complete materials list (for xxxxxx Glass) and do free pick up and delivery. It’s as easy as picking up the phone and saves you on mark up.
  1. 2) Can I apply privacy etching. No, sorry, you’ll have to do that yourself, however I’d be happy to bring the blocks over in advance.
  1. 3) Concrete foundation under block? No, framing is fine, double studded at the sides and studs every 16” underneath, or if steel framing requires double studding. They can be any height in the wall.

TOILET

Option 1a) require a 32 ½” x 48 ½” opening to allow for expansion strips on both sides and on the top. Code requires this, panel anchors and reinforcing every course, and fire caulk on one side, regular caulk on the other. All caulking and white glass block cement is covered with tile grout for a beautiful finish. ALL exterior openings need to be sheetrocked to pass inspection. Please include this out when sizing your openings. This applies to all openings.

Option 1b) require a 16 ½” x 72 ½” opening

BATHROOM

2a) 32 ½” x 48 ½” opening required.

2b) 32 ½” x 72 ½” opening required.

BEDROOM

3a) 64 ½” x 72 ½” opening.

3b) 48 ½” x 72 ½” opening

3c) 32 ½” x 72 ½” opening.

The cost for labor for this job is $xxxx.00. There’s a certain amount of labor involved and it doesn’t make much difference which window size you go with. You will save on materials cost with smaller windows. Payment is due upon completion.

Apart from the cost of the blocks, there would be additional materials, figure on $xx per block to include additional materials.

Hope this helps you.

<your name>

Sample Estimate #9

Hi <customers name>,

Your opening size needs to be an increment of 8”, plus 3/8”. For instance, 48 3/8” by 72 3/8”. The wood (at least 2×4) needs to be wrapped with a vapor barrier, such as black house wrap. Once the opening is correct size, and vapor barrier on, I can install the glass block.

Glass block to be installed in glass block cement, with panel anchors and reinforcing rod every course. Final finish of polyblend tile grout (snow white color).

Materials List

It’s important we have everything, as all suppliers have to order this in (only the distributor in the city carries stock, and they’re not open on weekends).

You need 54 8x8x4 glass block. (if you have 8x8x3, we can use that too) 3 bags of 4” spacers (unless you have 3” block, then it’d be 3 bags 3” spacers) 3 50lb bags of glass block cement 7 expansion strips 10 panel anchors 4 ten foot lengths of reinforcing rod

We’ll also need caulk and finish grout, but I’ll bring that so I have the right type.

The cost for labor would be $xxx, caulk & finish grout extra.

Please call me with any questions; we want to ensure it goes in one day with no problems.

Thanks, <your name>

Invoices

You have to have something printed out to give the customer. It doesn’t have to be fancy. Here are some to use as guides.

Sample Invoice #1

Hi <customers name>

Thank you for using me on your glass block installation. The window is built with glass block cement, panel anchors and reinforcing every course (and panel anchors on top too), with expansion strips on both sides and on top. The expansion strips are caulked with pittsburg-corning glass block caulk, inside and out. A skim coat of snow-white polyblend tile grout is used for the finish coat. The caulking at sides and along top is also finish grouted to hide the caulk.

For inspection purposes, panel anchors and reinforcing are visible if you bend down and look up at the bottom of the glass block. At some point on every course you will see panel anchors or reinforcing. Verification of caulk and expansion strips is also easy. Expansion strips are viewed through the side wall of the blocks, they are different color and texture from cement. Just chip the grout away at the side or on top to verify caulking, and patch chip.

If I can be of any service to you in the future please don’t hesitate to call me.

Installation of glass block window $xxxx

Please make check payable to <your name>

Thank you for your business!

Sample Invoice #2

Invoice for work to be performed

<customers name and address>

Installation of glass block shower wall, and two partition shower walls.

Channel anchor to be installed for glass block. Glass block to be installed with glass block cement, with panel anchors and reinforcing rod every course. Final finish of polyblend tile grout. Expansion strips to be used on the edges, between the channels and the glass block. Stylecaps to be installed on shower entrance.

Completion Wednesday May 4th, 2005

Installation cost: $xxxx- Additional materials (one bag of grout) $xx-

TOTAL COST $xxxx

Thank you for your business, <your name>

Sample Invoice #3

Mr <customers name>

Additional materials

  • 5 tubes of caulking - $30
  • 2 bags of snow white finish grout - $20
  • Labor

Total $xxxx

Thank you for your using my services in your renovation project. Everything came together great for the glass block installation. If I can be of any service in the future please keep me in mind.

Sincerely, <your name>

Job Issues You Might Not Think About

When we contemplate doing a job, we envison a successful outcome, and that endorphin rush of driving home with a wad of cash or a check in your pocket. But there can be issues that arise that lie outside of this utopian vision.

Many times when I was younger, I needed the work, and would give a decent bid on a job. In some cases the home owner or contractor would chisel me down on the price and I would have this butterfly feeling in my chest. But I would ignore that feeling as I wanted to work and needed the money. But every job that starts with problems (relationships too) always ends with problems, and the biggest one is getting paid promptly in full. I learned over time to associate that butterfly feeling with problem customers. After I recognized that my gut was informing me there would be issues, and I started listening to it, I found that the number of bad jobs was greatly reduced. Always remember that not every job is worth it, especially if the customer is concerned about costs and your profit margin will be too short. Glass block is not just construction work, it is also a status symbol, and it's not for everyone. If they can't afford you, they should choose another option. In this case, if you trust your gut, jack the price up to something ridiculous, and be so tightly scheduled that you don't have time for them, and don't sign anything!

Sometimes you may get a person who won't pay. We have covered how to get them to pay for the materials willingly, and should there be any problems with that, you should consider it as a failed credit check. Try to back out of the job or not be available. Any job that starts with issues will continue like that to the end. You are working and supplying labor, some materials, and your time. That sweat equity requires payment and it's up to you to know how to close the deal, deliver the invoice, and collect the cash or check. Offering a discount for cash on the day of completion is quite effective with most home owners, and agreeable to most workers.

You should set the terms of payment up front and write them on your estimate. You should also be firm, if some one can't pay, ask them why, then ask them when they will pay. This might sound like prying and none of your business, but after doing construction for many years you come to recognize a pattern, and the more uncomfortable you can make these people the better. If they don't pay ASAP, and you are realizing you might get scammed, you have to get tough. I used to give longer periods of time for non-payers when I started out, but you are the one who has to pay your helper, and you can be sure that the non-payer will not cut back on their steak dinners to ensure you are paid promptly. Learn how to file a 'lien'. This is a claim against their property filed with the local government or county government, depending upon your area. When they ask for extra time say that you have to be paid within 48 hours, and once an invoice becomes four days overdue your standard operating practice is to file a lien to ensure your right to payment. And then do it at 4 days! The home owner might not pay you right away, but at some point, unless they own their home outright, they will have to talk with the bank regarding their mortgage and the lien against the property that the bank is financing. You will get paid. You might also wish to tell them before hand that there is a $200 fee for filing a lien, not only does this pressure them, but it ensures that your time filing the lien, and your waiting period to get paid, is worth it. If the job is several thousand dollars, make the fee a fixed percentage, such as 15%.

You will sometimes have a resentful home owner. Perhaps they have gone over budget, or have run out of ice cream - whatever - but you are the one that has to deal with them. I had one customer who particularly was wasting my time, and on the day of the job, and after confirming with them the night before that it was ready, I arrived on site and had to wait five hours for the opening to be finished. I contained my impatience and frustration, and once I got going I knew I had to hurry to finish it before dark. Once it was complete the home owner said to me, “You know I've been watching you, and for the time you are working you are making waaaay too much money!”. I asked her if she had included the two trips to her house to consult, the 2 hour round trip into San Francisco to pick up the materials, the gas and bridge toll, and my time sitting around doing nothing for five hours. It made no difference to this person, but at least be prepared if you are questioned about costs and be sure to include all your expenses. This includes a dedicated phone line, website, truck, tools, laborer who you are paying to stand around do nothing for five hours, etc. The point is that you have to bid your jobs high to offset all these non on-the-job expenses.

Sometimes you have to deal with trouble-some people, usually other trades that may have attitude because of some aspect of the job that is not in your (or theirs) control. In the glass block trade it's usually tilers who think they can do glass block and didn't get the job. Just to clarify most tilers are not qualified to do this work, although they think they would like to tackle it, and I've had to fix many botched jobs by tilers. If some one has a big mouth and is trash talking you, you should confront them. It will be the only way to get respect and control of your project. Ask them to step outside and settle it, or to shut up.

Conclusion

At this point, if you have read all the above, or better yet practiced it, you will have a good working knowledge of how to install glass blocks in any type of window, any type of free standing wall, and how to replace a broken glass block.

Apart from your own practical experience, I feel I have passed on all of my knowledge and tips to install glass block successfully whether you be some one wanting to learn the art of installing glass block or a home owner ready to take on your own project. There were a few building code specific areas that I skipped over as they are only relevant to a specific area and could change at any time. But the basics remain the same and if you have read and absorbed this, it can be applied to any building code or any situation anywhere.

This was written with the intent to empower individuals to do their own projects in the absence of skilled glass block installers as the economic conditions in some countries have forced these artisans into other lines of work or retirement.

Glass block is a beautiful accent to any home or building and always elicits compliments. Your decision to install glass block in your home, or to install glass blocks as a business, will reward you many times over. If you learn some of your own tricks it is hope that you will pass them on so that the art of installing glass block will not disappear.

Why I Wrote This

This is not information that comes easily – the tips and tricks here have only come about through many years of experience passed down from glass block installer to glass block installer. With the recession that began in 2008 and the resulting slowdown in construction, the livelihood of the glass block installer has all but disappeared. Now that those of us with the knowledge have moved on to other lines of work or retired, and there is no one willing or wanting to do what little work is out there in regards to glass block, and the knowledge and skills will disappear.

It is hoped that this guide will enable any person who will put the effort into reading this to successfully undertake and complete their own project.

I left the trade due to a combination of factors including the recession, getting older, and life crisis. When I look back I am proud of the work I did and have good memories, but due to the economic and life changing conditions that surrounded my leaving the trade, I felt that it did not have proper closure. Writing the steps down here that you are reading now and imparting whatever knowledge I have at you is my way of passing on the torch. I feel that doing this gives me a proper sense of closure and writing this guide has enabled me to pour out all the information into one place so I can let it go.

Qualifications

I have been a brick and stone mason since 1986, and have worked my way around North America, both in Canada and the USA, and began installing glass blocks in Vancouver BC in 1990, and retired from the trade in San Francisco in 2008.

Last Revision

This page was last revised in October 2014. At this point in time it was receiving over 320 visits a month. I've decided it was time to look over the page, correct any glaring typos, and perform edits as required.

Thank you for visiting Devtome – the only place on the web where you get paid to write on whatever you want, completely uncensored.

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