MudAndTapeSheets, mud, tape and screws for a room, with the waste counted.

Ceilings & Special Cases

Ceilings, wet areas and fire-rated assemblies, where the ordinary rules change.

A ceiling is not a wall lying down. Three things change, and all three come from the standards rather than from preference.

Thickness depends on framing spacing

Half-inch standard board sags between joists at 24 inches on center. It looks fine for a season and then develops a slow wave that no skim coat corrects — and water-based texture makes it worse, because the board absorbs the water while it is unsupported.

At 24-inch framing you want ⅝ inch, or ½-inch sag-resistant board specifically rated for it. At 16 inches, standard ½ is fine.

Screws every 12 inches, not 16

A ceiling board fights gravity for its whole life. A wall board rests on the bottom plate. That difference is why ceiling fastener patterns are tighter, and why a ceiling screwed to wall spacing shows fastener pops first.

Boards run perpendicular to the joists

A board bridging several joists is far stiffer than one running along a single bay, and it spreads load across the joints rather than concentrating it.

Weight is the practical problem

A ⅝-inch 4 × 12 board weighs over 100 lb, overhead. A panel lift is not a convenience at that weight — it is the difference between doing the job and dropping a board on somebody. It also makes the joints tighter, because nobody is fighting the weight while positioning.

Mark the joists on the floor first

Once a board is up you cannot see the framing, and hunting for it with a screw gun leaves a ceiling full of holes that all have to be filled.

Waste runs higher than on walls

Ceilings get cut around lights, fan boxes, vents and the perimeter. Twelve percent rather than ten.

4 articles

How much drywall for a 15 × 12 ft ceiling?

Ceiling boards
5× ½″ sag-resistant 4 × 12 ft
180 ft² ceiling plus 12% — framing at 16″ o.c.
Ceiling planboards run across the joists · joists at 16″ o.c.5× ½″ sag-resistant 4 × 12 ft252 screws at 12″63 lb per boardSag: OK
Boards12% waste — ceilings cut around fixtures5½″ sag-resistant 4 × 12 ft
Ceiling area15 × 12 ft180ft²
Sag check½″ sag-resistant 4 × 12 ft is rated for framing at 16″ o.c.OK
Screws12″ spacing on ceilings, not 16″ — about 1 lb box252screws
Joint compound0.54.5 gal buckets
Paper tape96linear ft
Weight per boardoverhead — a panel lift is worth the hire, and it is not optional on ⅝″ 12 ft boards63lb
Fixture cut-outscut after the board is up, from the joist positions marked on the floor2holes

Notes

  • ½″ sag-resistant 4 × 12 ft is rated for 16″ framing. Note it is the board that carries the rating, not the paint or the texture over it.
  • Screws every 12 inches on a ceiling, not 16. A ceiling board fights gravity for its whole life; a wall board rests on the plate. That difference is why ceiling screw patterns are tighter, and why a ceiling that was screwed to wall spacing shows fastener pops first.
  • Run the boards perpendicular to the joists. A board bridging several joists is far stiffer than one running along a single bay, and it spreads the load across the joints instead of concentrating it.
  • Each board weighs 63 lb overhead. Two people can manage it, but a panel lift makes the joints tighter because nobody is fighting the weight while positioning.
  • Mark the joist positions on the floor before you lift a board. Once it is up you cannot see them, and hunting for framing with a screw gun leaves a ceiling full of holes.
  • 12% waste rather than the 10% used on walls — ceilings are cut around 2 lights, plus any fan boxes, vents and the perimeter.

Ceiling drywall

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