Let There Be Light! Use Glassblock Windows and Walls

I think I'm in love, I found something new to faun over at Menards, glass block windows. I remember these from the 1950's when my aunt and uncle built their house. Today, there's so many neat designs that I've fallen into mesmerization again. (Yes, as you recall from other articles, I have no social life except a weekly trip for supplies with Mike and our trip for senior discount day at the grocery. You can probably understand why the outside world enthuses me.) If you want a lot of light in your bathroom but aren't crazy about the idea of the neighbors seeing you shower, glass block windows may be a good choice for you. These windows let in light, yet don't allow those outside to see anything.

Glass block windows aren't new; in fact, they began as far back as the 1800's and used on ships and in cellars as a method of providing light. When glass changed from blown to glass manufactured by machine in 1903, it brought new advances for glass block for windows. By 1907, the machines produced solid glass blocks, which builders combined with reinforced concrete block to give light to the structures. The mortar around the glass blocks was the same as used for other concrete projects. Other innovations at the time were hollow glass blocks. These weren't as successful even though they provided more insulation value. Since they were hand blown, they didn't have the consistency necessary for building or ability to be mass-produced. In the 1930's Corning-Stueben created a machined rectangular block that had two sides pressed together for a hollow center.

The hollow block gave more protection from loss of heat and noise protection. The thick walls surrounded a layer of air and when the two sides were sealed, the block was a brick and the same shape as other, concrete building materials. This made construction with the hollow glass blocks easier. The blocks still had air on the interior and changes in temperature caused condensation.

Today's hollow glass blocks have additives that give extra strength to it. After the glass making material melts, the manufacturer pours it into a male and female mold, which creates two halves. These fuse together and a special machine creates a 70 per cent vacuum. The vacuum stops condensation of the air on the interior of the block and makes them far more beneficial in building than the earlier ones. The newer glass block windows use special mortar created for glass. You mortar the blocks with shims to hold the glass block in place, then remove the shims and mortar those openings.

Newer glass block windows come preassembled from the factory. This makes installation a lot easier for the novice and eliminates the use of mortar. The windows with frames less than 6 feet are easy enough to install when they come prefabricated from the factory. There are glass block windows that open and ones that simply allow the light to shine through them on the market today. These windows seldom require any upkeep, except the occasional spray down with a hose and cleaning on the inside.

According to Pittsburgh Corning, a 1/8 inch flat sheet Pittsburgh Corning Mortared Glass block window has the same energy efficiency as a double pane window and often is less expensive. There's no need for blinds, drapes or other window treatment since they are for privacy. Glass block windows allow you to replace each individual block, but breakage is far more difficult and they resist illegal entry. They act like a wall of concrete so the weather isn't a problem.

The block windows come in a variety of sizes and shapes. If you choose, you can buy the blocks, use spacers, and a special mortar to create your own. The mortar contains Portland cement, crystalline silica and sometimes lime or latex polymer, dolomite and sodium naphthalene sulfonate. Some windows that you build from block don't require mortar and use a silicon sealant for the final finish, although many construction experts prefer epoxy fortified grout.

Be careful when you use mortar for glass block windows. Wear a mask, gloves and protective eye gear when you mix it. Prolonged exposure to the skin may cause irritation. The crystalline silica can scratch the surface of the eyeball and is potentially dangerous if chronically inhaled. Never mix more than you can use in about a half hour. For some mortar mixtures, mix enough for only 15 minutes. If it starts to dry, don't try to add water to salvage it. Toss the batch and mix new. Over mixing and adding water just kills the batch.

We're now designing the remodeling of the house and I definately want a whole wall of glass block. Just like the Ghost Whisperer, I can then tell my company, "If you want a chair, just walk towards the light."