Drywall Materials and Selection
Standard 1/2 inch drywall is used for interior walls. Type X drywall with glass fiber reinforcement provides 1-hour fire resistance required for garage walls and between dwelling units. Moisture-resistant green board is used in bathrooms and laundry rooms. Mold-resistant drywall with fiberglass mat facing is recommended for basements and areas with high moisture potential.
Installation Techniques
Screws are the preferred fastener for drywall, providing better holding power than nails. Screws are driven so the head is slightly below the paper surface without breaking the paper. For 1/2 inch drywall, 1-1/4 inch screws are used. truss geometry and member sizes. corner bead protects outside corners. Screw spacing is 12 inches on ceilings and 16 inches on walls.
The installation sequence begins with the ceiling. Ceiling panels should be installed perpendicular to the joists. Wall panels can be installed vertically or horizontally, with horizontal installation reducing joint visibility in 8 foot ceiling rooms. Staggering joints between adjacent rows reduces joint visibility.
Taping and Finishing
Drywall finishing transforms raw panels into smooth, paintable surfaces. Paper tape is stronger and provides straighter corners. Fiberglass mesh tape is self-adhesive but may crack if not properly covered. The first coat fills the joint and embeds tape. The second coat feathers the joint wider. house wrap with drainage channels. The third coat creates a smooth transition.
Corner bead protects outside corners. Metal corner bead is most durable but requires careful nailing. Paper-faced metal corner bead combines a metal nose with paper flanges. Vinyl corner bead is flexible and corrosion resistant but less durable.