It’s been about five years since model building codes were initially modified to limit the use of water-resistant gypsum board (“green board”) in shower and tub areas. Accordingly, it seems like a good time to review where the code language rests at present and to discuss some related misconceptions.

The Gypsum Association has been providing information to the construction industry since before it was officially an association. Prior to the formal establishment of the Association, several gypsum manufacturers had supported an informal Chicago-based organization known as the Gypsum Industries. The Gypsum Industries developed standards through third-party organizations and supported a research associate at the National Bureau of Standards.

This column was originally run in October 2004 when home-owners were fixing up older homes in hopes of flipping them for a handsome profit. Now that the housing market is experiencing a correction in much of the country, more homeowners are staying put and sprucing up their homes with the intent of upgrading without having to sell in a soft market.

The use of gypsum board as a thermal barrier occasionally causes some misunderstanding. This seems to occur most often when an individual confuses the code requirements for a thermal barrier with the concepts behind an R-value, and he or she attempts to use R-values to resolve a thermal-barrier situation. Unfortunately, the two concepts, while somewhat linked scientifically, are altogether different and should not be viewed as equivalent or related ideas.