How Much Drywall for a 15x15 Room?
Drywall sheets
25 sheets
Four walls at 8 feet tall plus a 15 by 15 ceiling: 705 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 cover705 sq ft
- Sheet size4 x 8 ft, 32 sq ft
- Waste allowance10 %
Drywall sheets25 sheets
| Area with 10% waste | 776 sq ft |
|---|---|
| Sheets at 32 sq ft | 25 |
| Joint compound, 4.5 gal buckets | 2 |
| Joint tape | 295 lf |
| Screws | 800 (about 3 lb) |
| Corner bead, rough guess | 47 lf |
The material list this produces
| Drywall sheets | 25 |
|---|---|
| Joint compound, 4.5 gal buckets | 2 |
| Joint tape, linear ft | 295 |
| Drywall screws, lb | 3 |
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 | 25 sheets |
| 4 x 10 ft | 20 sheets |
| 4 x 12 ft | 17 sheets |
What else matters here
Fifteen feet is the length that makes this room worth its own page. An eight foot sheet run horizontally covers eight feet, a twelve foot sheet covers twelve, and neither reaches fifteen, so every wall in this room carries a butt joint no matter what is bought.
That is the difference between the two kinds of joint. The long edges of a sheet are tapered, so where two of them meet there is a shallow trough that compound and tape sit down into and finish flush. The cut ends are square, so a butt joint is a hump that has to be feathered out twenty inches or more either side to become invisible.
Place them deliberately. Butt joints belong away from the eye and away from a window, because raking light across a wall finds them. Stagger them so they do not line up from one row to the next, and if the wall is going to be finished in a gloss or lit from the side, a butt joint backer board is worth the extra hour.
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 15x15 room?
Twenty five sheets of 4 by 8 for walls and ceiling, with a ten percent waste allowance.
What is the difference between a butt joint and a tapered joint?
Tapered joints are the factory long edges, which form a shallow trough that finishes flush. Butt joints are cut ends meeting square, which leaves a hump to feather out.
Where should drywall butt joints go?
Away from windows and away from eye level, staggered so they do not line up row to row. Raking light across a wall shows every one of them.
The drywall calculator takes any dimensions you like and hands back the same list.