Q&A / 

Glass Block

Block windows have really created lots of consumer interest in the past 20 years. I actually remodeled the office and fabrication shop space when the first glass block company moved into the Cincinnati, OH market. I was astonished by the precision laying framework that was used to make the individual sized panels. At the time, I thought it would be a passing fad. Good thing I didn't bet on that!

A Commercial Product

Glass blocks have been around for nearly 80 years. They are a classic art deco building material. Block windows also were in vogue in the 1950's and 60's as well. Fifteen years ago, things really got interesting.

The block windows were originally used in commercial and industrial applications. Frank Lloyd Wright used them in a house located only 3/4 of a mile from my house. I guess if he can use them in a house, it is OK!

Whatever the reason, millions of them are being used around the world in residential construction every year. They are practical in many applications. You can even purchase clear block windows that pivot and open just like any old casement window. That opens up all sorts of possibilities......no pun intended.

Installation Skills Vary

Complicated installations of glass block require skills of a master mason. Large block panels require horizontal wire reinforcing. Special hidden anchors are used on the sides of the block as they are laid.

Things are a little different if you choose to use a lightweight clear acrylic block. These block are available in large panels that come assembled from the factory. They weigh much less than traditional glass block.

Windows less than 6 square feet in size can be tackled by an average homeowner. This is because fabricators have sprung up in all corners of the nation. These people pre-make the windows for you. You simply install one large panel.

The pre-made panels are also available at many home center stores. Just one month ago, a friend of mine purchased two to install in a rehab job. He walked right in and BINGO, there were the right sized windows. It couldn't have gone smoother if you tried.

Caulking Method

The maker of the glass blocks has developed a method that allows you to install glass block piece by piece using vertical and horizontal spacer strips and clear silicone caulk. I haven't tried this method. If you try it, I suggest that you have plenty of lacquer thinner on hand to remove silicone caulk smears.

Excellent Literature / Videos

Because of the widespread popularity, the block window manufacturers have created many helpful pamphlets, booklets and videos to help you design and complete your glass block window projects. All you have to do is call them and order these materials. It is also quite possible that these materials are available at local distributors.

Pricing Varies

I received a phone call from a Michigan reader. He informed me that he can get an average basement block window installed (all labor and materials) for less than $50 per window! That is a superb deal. The price here in Cincinnati is almost twice that. I guess there is a savage price war happening in Michigan!

When you are shopping, be sure that you are comparing blocks that are the same thickness. Ask for copies of both Worker's Compensation Certificates and General Liability Insurance. Low price installers generally work without these important policies!

If you decide to have a company install your windows, do not pay more than 25 percent as a down payment. Your state law may even permit you to pay less. Beware of individuals who demand 50 percent or more.

Energy Efficiency

The block windows that do not open offer great energy savings. The reason lies in the fact that they can reduce air infiltration to zero. Many old basement windows were poorly weather stripped.

If you do intend to install these windows in your basement and you have gas (or oil) furnaces and water heaters, PLEASE have the fabricators install a 4 inch piece of PVC pipe in the window(s) closest to the equipment. This will allow you to run a combustion air pipe to the appliances.

Remember, these devices need massive amounts of fresh air when they are burning. Your new windows will rob these appliances of their air supply unless you provide the opening. This feature will cost less than $10 per window on average.

Custom Shower Bases

Do you want a glass block shower stall? It couldn't be easier! Pittsburgh Corning makes three different styles and my favorite is the walk in shower. It requires no shower door because of a 90 degree curved wall that captures the water spray. It is so cool! The acrylic bases come in seven colors to boot. They are made to support the weight of the glass block so there is no fear of fracture over time. The built-in flashings are also a swell feature.

Author's Note: We've received other questions with similar problems or questions. Here's one from Lena K. of Rockville, MD, regarding basement replacement windows.

"Our basement windows leak air as well as water when snow melts. The house was built in 1965 and the windows seem to be from that time. They are below the ground level with wells dug out around them. They are set directly into concrete blocks. I looked at different replacement window manufactures and installers, and none of the ones I saw offer specific windows for basements. Do you have any suggestions? (We aren't planning on doing the replacement ourselves). Thank you."

Companion Articles:  Glass & Acrylic Blocks Do Many Things, Glass Block Installation, Glass Block Manufacturers, Glass Block Greenhouse

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