As a tilesetter, I have been working with glass blocks for years. I started out with simple "enclosed" panels (small areas of glass block surrounded by framing) and then, through experimentation, moved on to more open and freestanding designs. Thanks to special additives that greatly increase the mortar's strength, dramatic uses of glass block not possible ten years ago are becoming commonplace, especially in commercial buildings. At present, there is not an industrywide standard for either large commercial work or residential applications. However, Pittsburgh Corning Corporation, the only manufacturer of glass block in the U.S., has conducted extensive research and provides good technical literature (see "Glass Block Sources and Materials"). They can also provide technical advice by telephone to help you with difficult or unusual
