Drywall is best fastened with drywall screws—typically black phosphate-coated, coarse threaded screws that are 11⁄4" long. Until the rise of the countersinking screw gun, drywall was installed with hammers and ring-shank drywall nails. Nails still have some uses: for example, the initial securing of hard-to-reach portions of wall and ceiling panels. Nails are also often used for securing metal corner bead because they create less distortion of the bead than an over-driven screw. Ring-shank drywall nails should penetrate framing by at least 3⁄4". Nails cannot be used with metal wall studs and framing. Because screws hold drywall more securely than nails, you may employ greater fastener spacing with them.
Drywall screws are categorized by letters, indicating the type of framing they are best suited to be used with. For wood framing, select Type W screws that penetrate the framing by at least 5⁄8". For steel framing or to secure gypsum panels to resilient channels, use fine-threaded Type S screws that penetrate the metal by at least 3⁄8". Use drill-point Type S screws for heavy-gauge steel. To screw gypsum to gypsum in double layers until an adhesive sets, use course threaded Type G screws. Alternatively, use longer Type S or W screws to attach panels to the framing.
Special screws are made for other non-drywall panels. Cement board is best fastened with cement board screws that self-tap into the hard cement board surface and then resist corrosion in the damp, alkaline environment. Use fine threads for steel framing and coarse threads for wood framing. Hot-dipped galvanized roofing nails may also be used to secure cement board and other tile backers to wood framing.
Some drywall installations also call for the use of adhesives. Ordinary joint compound can function as an adhesive when applied between drywall layers in a two-layer wall. Panel adhesive may be used to laminate drywall panels also. Panel adhesive applied to studs or joists can reduce fastener needs by 75 percent and eliminate the possibility of panels rattling. A spray-on adhesive is used to attach vinyl corner bead to drywall.
Acoustical sealant (caulk) fills openings and cracks that let sound through walls and ceilings and helps isolate drywall panels from the vibration of adjacent surfaces. Used around electric boxes and floor-to-wall seams, it's the least expensive way to improve STC (sound transmission class) ratings. It can also reduce heating and cooling needs by blocking air gaps.
