Section R702 specifies that interior wall finishes include gypsum board (drywall) fastened to framing. Thickness depends on framing spacing, with 1/2 inch used for 16-inch spacing and 5/8 inch for 24-inch spacing. Fastening uses screws or nails spaced 12-16 inches on center. Joint compound fills seams between sheets, creating a smooth surface for painting. Multiple coats of joint compound are required, with sanding between coats. Fire-rated gypsum board (Type X) contains glass fiber for improved fire performance. Moisture-resistant (MR) gypsum board is used in bathrooms and other damp locations.