In North America, drywall is the most common interior wall and ceiling finish material. Normally, it is composed of paper on both exterior surfaces, which is laminated to a gypsum core. Drywall is easily damaged while wet, since it loses much of its strength and stiffness. If not wet for extended periods (i.e., 48-72 hours), drywall normally regains its original strength upon drying.
If drywall requires replacement, restorers using appropriate PPE should accomplish area containment and drywall removal first; then properly dry exposed wood framing to within four percentage points of normal EMC. At a minimum, wood framing materials should be below 16% MC before installing new drywall. Failure to do so can result in mold growth where moist wood contacts drywall, paneling or other wall covering materials. Also, reinstalling drywall over wood studs with excessive MC can contribute to “nail pops” or joint cracks as wood studs continue to lose moisture and shrink.
Gypsum board materials have recently become available that use fiberglass or other non-nutritive materials, rather than paper, for the facing on the interior only or on both sides. It is recommended that water and microbial-resistant materials, such as these, be considered when re-installing drywall, especially in areas more likely to become wet again.