Drywall (also called gypsum board, Sheetrock®, or plasterboard) is the standard material for interior wall and ceiling surfaces in residential and commercial construction.
Common Sizes
- 4×8 ft: Most common residential size (32 sq ft per sheet)
- 4×12 ft: Fewer seams for ceilings
- Thickness: 1/4" (curved walls), 3/8" (overlay), 1/2" (standard), 5/8" (fire-rated/ceilings)
Estimating
Total square footage of walls ÷ 32 = sheets needed. Add 10–15% for waste and cuts.
Fire-Rated and Moisture-Resistant Types
Type X drywall (5/8" thick, with added glass fibers) is required by building code between garages and living spaces and around furnace rooms for fire resistance. Moisture-resistant "green board" or cement board is required in bathrooms and other wet areas — standard drywall in these locations will eventually degrade and grow mold.
Why Seams Need Multiple Coats
A finished drywall seam typically needs three coats of joint compound (tape coat, fill coat, finish coat), each sanded and feathered wider than the last, to disappear invisibly once painted. Rushing to one thick coat instead almost always results in visible seams once the wall is lit at an angle.