Drywall is a funny name for gypsum-based wallboard. Gypsum itself contains a good deal of water as it is typically formed from the evaporation of saline water. When heated, some of the water is evaporated, but the typical Flue-Gas Desulfurization (FGD) gypsum that makes up about 50% of the gypsum products used in the US still contains quite a bit of water.
In fact, the presence of water allows for one of gypsum wallboard’s most important applications in the built environment — fire protection. As gypsum is heated, that water is released as steam, retarding the spread of fire.
Gypsum wallboard happens to be not very resilient however, in the presence of additional water. In fact, when so-called “drywall” becomes wet, it becomes an almost perfect environment for promoting the growth of mold. For that reason, the various trade organizations supporting the gypsum industry have recommended that any drywall that has come in contact with water be replaced.
Hurricanes + Flooding = Lots of Gypsum heading to the landfill
To assist with post-hurricane rebuilding efforts, the Gypsum Association, a not-for-profit trade association founded in 1930, has placed all relevant technical documents pertaining to gypsum board (AKA drywall or wallboard) on a single, easy to locate webpage along with answers to frequently asked questions associated with repair and replacement after water damage.
These technical resources lay out proper methods of handling, storage, repair, and replacement of gypsum board. As always, consumers, building professionals, code officials, inspectors, and building product distributors can access these technical resources online and free of charge.
The Gypsum Association’s webpage with resources for homeowners and professionals can be found here: Hurricanes and Flooding: Gypsum Association Technical Resources. Among the various technical guides, there is a manual that was prepared with input from numerous agencies including the CDC, EPA, NIH, FEMA and HUD. You can download a PDF version of the document here: Homeowner’s and Renter’s Guide to Mold Cleanup After Disasters.
Another document that is worth saving a copy of, not just for hurricane and flood situations, is the GA-231-2015 Assessing Water Damage to Gypsum Board publication.
Image courtesy AF.mil