How do I assess water damage to drywall?
When gypsum board is exposed to elevated levels of moisture, an assessment of the potential damage to the gypsum board must be made as to whether board exposed to these conditions should be replaced. Gypsum board may experience limited intermittent exposure to moisture from a variety of sources, such as improper storage, construction or design defects, water leaks and janitorial activities. Gypsum board exposed to water should be replaced unless all of the following conditions are met.
The source of the water or moisture is identified and eliminated.
The water or moisture to which the gypsum board was exposed was uncontaminated.
The gypsum board can be dried thoroughly before mold growth begins (typically 24 to 48 hours depending on environmental conditions).
The gypsum board is structurally sound, and there is no evidence of rusting fasteners or physical damage that would diminish the physical properties of the gypsum board or system.
CAUTION: When replacing gypsum board in a fire resistance or sound rated system, care must be taken to ensure that all repairs are consistent with the specific fire or sound rated design initially constructed (gypsum board type, fasteners and their spacing, and staggered joints).