Glass Blocks

Glass blocks are a special building material made of glass or acrylic. Shaped and laid similarly to brick or concrete blocks, glass blocks are available in several different sizes and are commonly used as an alternative to traditional windows, especially in basements. Glass blocks are also used to construct shower walls, uniquely shaped windows, and are frequently employed in the architectural design of office buildings. 
For residential purposes, glass blocks are most commonly used as an alternative to basement windows. Being located at ground level, basement windows are considered easy access to a home. Glass block windows are more difficult for would-be thieves to penetrate and thus considered a more secure alternative to traditional basement windows. Other common residential uses for glass blocks include shower walls and uniquely shaped and located windows. 
Glass blocks are also frequently found in office spaces. They can be used to construct non-load bearing walls, partitions, and windows. Glass blocks are considered both an architectural element and a practical aspect of design because natural lighting can be filtered in. 
Glass blocks come in a variety of designs as well as sizes. They may be opalescent or clear and are also available tinted with hints of various colors. Installation typically involves grout and mortar, but some manufacturers of acrylic glass blocks use alternative installation methods for their glass blocks, such as interlocking PVC joints. 
Homeowners can replace existing windows with glass blocks, but should keep in mind that a conversion renders the window inoperable, making it only a source of light. However, many windows are located or shaped oddly and are non-functional anyway. Glass blocks are also considered more energy efficient than traditional plate glass windows.