How Much Drywall for a 20x20 Garage?
Drywall sheets
36 sheets
Four walls at 8 feet, plus a 20 by 20 ceiling: 1,040 square feet, no openings deducted.
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How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Total area to cover1040 sq ft
- Sheet size4 x 8 ft, 32 sq ft
- Waste allowance10 %
Drywall sheets36 sheets
| Area with 10% waste | 1,144 sq ft |
|---|---|
| Sheets at 32 sq ft | 36 |
| Joint compound, 4.5 gal buckets | 3 |
| Joint tape | 435 lf |
| Screws | 1,152 (about 4 lb) |
| Corner bead, rough guess | 69 lf |
The material list this produces
| Drywall sheets | 36 |
|---|---|
| Joint compound, 4.5 gal buckets | 3 |
| Joint tape, linear ft | 435 |
| Drywall screws, lb | 4 |
Sheet size compared
Longer sheets mean fewer butt joints and less taping. Same area, three sheet sizes.
| Sheet size | Drywall sheets |
|---|---|
| 4 x 8 ft | 36 sheets |
| 4 x 10 ft | 29 sheets |
| 4 x 12 ft | 24 sheets |
What else matters here
A garage is mostly ceiling, and a garage ceiling is usually the part the building code has an opinion about. Where a garage is attached to a house, the separation between them typically has to be five eighths inch type X board, and where there is living space above, the whole ceiling does.
That changes the order, not just the thickness. Type X is heavier, costs more, and is not interchangeable with standard half inch on the walls that form the separation. Check the local code before ordering, because getting this wrong is a failed inspection rather than a cosmetic problem.
Thirty six sheets is about 1,800 pounds of board. Have it delivered and, if the supplier offers it, have them boom it in through the garage door rather than stacking it on the driveway.
What this calculator assumes
- Joint compound is figured at one 4.5 gallon bucket per 475 sq ft of board for a full three coat finish. A level 5 finish uses more.
- Tape is figured at 380 linear feet per 1000 sq ft of board, screws at 32 per sheet for 16 inch on center framing.
- Longer sheets mean fewer butt joints, which is less taping and a flatter wall. Use 12 footers where they will fit through the door.
Questions people ask
How many sheets of drywall for a 20x20 garage?
About 36 sheets of 4 by 8 for walls and ceiling, with ten percent waste. Use 5/8 type X where the code requires fire separation.
Does a garage need fire rated drywall?
Usually on the wall and ceiling between the garage and the house, and on the whole ceiling if there is living space above. The exact requirement is local, so confirm it with your building department.
Do I need to insulate before drywalling a garage?
If the garage is attached or you plan to heat it, yes, and it is far cheaper now than later. There is an insulation calculator on this site for the bag count.
The drywall calculator takes any dimensions you like and hands back the same list.