Roof geometry, framing layout and material takeoffs

Sheet Goods Chart

The number that governs a sheet of drywall on a ceiling is not its thickness alone — it is thickness against framing spacing. Half inch board is standard on walls everywhere and sags on ceilings framed at 24 inches. Below are thicknesses, weights and coverage, alongside the sheet sizes, because the weight of a 12 foot sheet decides how it gets into the room.

Generated from the same data the calculators use — a chart and a calculator on this site cannot disagree.

Gypsum board — thickness, weight and where each is used

Board Thickness Weight Weight of a 4 × 8 sheet Typical use
1/4 inch 0.25"0.8 lb/ft²26 lbSkimming over existing surfaces and curved work. Not a substrate on its own.
3/8 inch 0.375"1.2 lb/ft²38 lbRepairs and double-layer work. Rare as a single layer in new construction.
1/2 inch 0.5"1.6 lb/ft²51 lbThe standard for walls, and for ceilings framed at 16 inches on centre.
1/2 inch lightweight 0.5"1.2 lb/ft²38 lbSame thickness, roughly a quarter lighter. Easier overhead, slightly softer face.
5/8 inch Type X 0.625"2.2 lb/ft²70 lbFire-rated assemblies, garage ceilings under living space, and any ceiling framed at 24 inches on centre.

Sheet sizes and coverage

Size Area Sheets per 1,000 ft²
4 × 8 ft 32 ft²32
4 × 9 ft 36 ft²28
4 × 10 ft 40 ft²25
4 × 12 ft 48 ft²21
54 in × 12 ft 54 ft²19

How to read this chart

Structural panel span ratings are not listed here. A sheathing panel is selected by the span rating stamped on it — two figures such as 24/16, giving the maximum roof and floor support spacing — and not by its nominal thickness. Read the stamp on the panel in front of you rather than a table.

Half inch gypsum board is standard on walls everywhere, and on ceilings only where the framing is at 16 inches on centre. At 24 inches it sags between the joists, permanently, and water-based texture accelerates it. Use 5/8 inch or half inch sag-resistant ceiling board.

Weight decides how a sheet gets handled. Anything much over 55 pounds overhead is a two-person lift or a panel hoist, and a 12 foot sheet of 5/8 inch board is over 100 pounds — which is the whole reason lightweight board exists.

Every wood panel needs an 1/8 inch gap at edges and ends. Panels take on moisture and grow; butted tight they have nowhere to go and buckle in visible ridges.

Sources

  • Standard gypsum board thicknesses and weights
  • Manufacturer panel edge gap instruction — 1/8 inch at edges and ends

Reference values. Board weights vary by manufacturer and product. Structural panel selection is governed by the span rating stamped on the panel and by wind, seismic and snow requirements, none of which are covered here.

Frequently asked questions

What does 24/16 mean on a panel?

Maximum support spacing in inches — 24 when the panel is used as a roof deck, 16 as a subfloor. It is the number that decides whether a panel suits your framing, and it is not the same thing as thickness. Read it from the stamp on the panel.

Is 1/2 inch plywood actually half an inch?

No. It is 15/32, and 3/4 inch is 23/32. The nominal names describe the pre-sanding thickness. It matters wherever a panel meets something dimensioned exactly, such as a stair or a threshold.

Can I use 1/2 inch drywall on a ceiling?

Only at 16 inch framing spacing. At 24 inches standard half inch board sags between the joists over time. Use 5/8 inch or half inch sag-resistant ceiling board.

How heavy is a sheet of drywall?

A 4 × 8 sheet of half inch board is about 51 pounds, and a 12 foot sheet of 5/8 inch is over 100. Anything much above 55 pounds overhead is a two-person lift or a panel hoist, which is the whole reason lightweight board exists.