Tips for Building with Glass Block

Glass block is certainly popular in contemporary houses, both for exterior windows and interior dividers. Many pools use it around the spa and pool also. One model home I saw had a circular shower totally made of glass block. Pretty it is and pretty expensive also! But there are places that seem made just for glass block. Many pool spas’ have glass block separating the spa from the pool, forming a beautiful transparent liquid waterfall from the spa. Another application is on exterior stucco fences, where the glass block “lightens” the apparent height of the wall, while still providing privacy.

In Florida and other southern states, the use of glass block should be restricted where the direct sun will not reach the glass block. Glass is a good conductor of heat and light, and you will find too much of both on the inside if it is exposed to the sun directly. Placed where it can transmit light and shadows to the inside, it will give you the light you desire and still provide some privacy. Different forms of glass block provide more or less privacy. Some you can almost see through while there are others impossible to see anything. It also comes in several different sizes, shapes and corners, enabling almost any form to be constructed.

For exterior locations or where it will be exposed to water, specify waterproof Portland cement as the bonding agent or one of the proprietary cements made especially for glass block. Other ways to join it are with a caulk type of cement and there is even a plastic runner to hold the block to another block for locations where you might want to move it at a later date. Probably there are more applications today than ever in the history of glass block.

Most block made in the United States is maunfactured by Pittsburgh-Corning. Corning- Steuben invented the process in 1902! They were made individually in block molds then and the two halves were pressed together at very high temperatures, the hot air cooling inside forming a vacuum when cooled. In the beginning they were hand blown into molds, but the moisture from the glassblowers lungs would condense and form water drops on the inside. For several years glass block was out of favor as a building material, and anyone wanting any had to find a wrecking yard that could take down a glass block wall without breaking them! Today there are manufacturers in Japan and Europe as well as the US. making it.

Back to the question, “Can we make the outside wall of the shower glass block?” The answer is yes, if you can stand knowing your silhouette, both reality and illusion, will come through at night. There will be light and shadow, substance and illusion, an altogether beautiful sight, made possible only by glass block.