Drywall (sheetrock) is the interior finish most commonly used in residential construction. The following guidelines pertain to its application.
When practical, wallboard should be applied first to the ceilings, and then to walls. Sheets should be brought into contact but not forced into place. Spaces between sheets should not exceed 1/4" and tapered edges should be placed next to each other when possible. Drywall should extend at least 6" past door and window openings, except where this is impossible.
Cutouts for electrical outlets, pipes, fixtures or other small openings should be cut out neatly with a maximum clearance of 1/4". If there are any gaps exceeding 1/4", they must be filled with taping cement, Fixall or other approved materials. These gaps and holes must be filled before the drywall is inspected, but do not tape joints prior to inspection.
Nails should be driven so that the head is in a small dimple formed by the last blow of the hammer. Take care not to fracture the board when nailing. Fractures of the wallboard caused by over driving must be corrected by additional nailing. Nails must be between 3/8" and 1" from the edges, and nails on adjacent edges should be opposite each other. If you are using the single nailing system, the nails should be spaced 7" on center on the ceilings and 8" on center on the walls. The double nailing system is also permitted. Groups of 2 nails 2 - 2 1/2" apart are spaced 12" on center in this system. Approved screws may also be used to apply wallboard. Screws must be placed 3/8" from the end or edges of the board and spaced 12" on center. Screws must be used for fastening wallboard at pocket doors.
All metal reinforced corners must fit snugly against wallboard and should be nailed approximately 12" on center. All "L" edge metal trim should be nailed every 6". Paperback corner bead is acceptable if installed as per the manufacturer's instructions.
Drywall In Shower Enclosures
When gypsum board is used as a base for tile or wall panels for tub or shower enclosures, water-resistant gypsum backing board shall be used. Nailing of the drywall in a shower enclosure is the same as for any other area; however, additional treatment may be required depending on what system is used to install tile or other wall finishes. Check with the Building Inspector for further requirements in this area.
Drywall In Fire-Resistive Construction
There are two areas in residential construction where one-hour fire resistive construction is required. One area is the wall separating an attached garage from the living area, and the other is enclosed usable space (walls and ceilings) under a stairway. A one-hour firewall is constructed as follows: 5/8" type "X" gypsum wallboard is nailed 7" on center with 6d "cooler" nails to studs spaced 16" on center. All gaps and penetrations must be filled with taping cement or stuffed with non-combustible material such as fiberglass insulation.
|3/8" thick drywall:|
|4d cement-coated box nail, or|
|1 1/4" - 14 gauge, acid-etched, phosphate coated nail, or|
|4d "drytite" nail|
|1/2" thick drywall:|
|4d cement coated box nail, or|
|1 3/8" - 14 gauge, acid-etched, phosphate coated nail, or|
|4d "drytite" nail|
|5/8" thick drywall:|
|6d cement-coated box nail, or|
|1 1/2" - 14 gauge, acid etched, phosphate coated nail, or|
|5d "drytite" nail|
Any other nail or fastener with ICBO approval may also be used. (Fire resistive construction must comply with Table 7B of the 1994 Uniform Building Code).