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USG's installation data for its 1/2 in Sheetrock UltraLight panels calls for 1-1/4 in Type W bugle-head screws complying with ASTM C1002, spaced no more than 12 in apart on ceilings and 16 in apart on walls for a single layer over wood framing, and its fastener FAQ gives the same spacing for steel framing. A sheet hung across the framing is fastened down every stud or joist it crosses, so the Drywall Screw Calculator counts screws per sheet as framing members crossed × screws down each member. A 4 ft wide sheet takes 4 screws down each stud at 16 in spacing and 5 down each joist at 12 in, and a 4 × 8 sheet crosses 7 framing members at 16 in on center: 28 screws on a wall and 35 on a ceiling, or 20 and 25 on 24 in framing. It multiplies by your wall and ceiling sheets and adds an allowance, 10% by default, for dropped and stripped screws. A 12 × 12 ft room with 14 wall sheets and 5 ceiling sheets takes 567 screws, 624 with 10% extra.
| Sheet | Wall, 16 in o.c. | Ceiling, 16 in o.c. | Wall, 24 in o.c. | Ceiling, 24 in o.c. |
|---|---|---|---|---|
| 4 × 8 ft (32 sq ft) | 28 | 35 | 20 | 25 |
| 4 × 10 ft (40 sq ft) | 32 | 40 | 24 | 30 |
| 4 × 12 ft (48 sq ft) | 40 | 50 | 28 | 35 |
| 54 in × 12 ft (54 sq ft) | 40 | 50 | 28 | 35 |
Android: Smart Drywall Calculator on Google Play. iPhone: the drywall calculators are inside Roofing Calculator & Estimator on the App Store.
At USG's maximum screw spacing — 16 in apart on walls and 12 in on ceilings, single layer — a 4 × 8 sheet hung across studs 16 in on center takes 28 screws on a wall (7 studs × 4 screws) and 35 on a ceiling (7 joists × 5). Many installers round up to about 32 per wall sheet. On 24 in framing it is 20 and 25.
USG specifies 1-1/4 in Type W screws no more than 12 in apart on ceilings and 16 in apart on walls for single-layer gypsum panels over wood framing; its FAQ gives the same spacing for steel framing. Nails go closer: 7 in on ceilings and 8 in on walls. Fire-rated assemblies follow the tested design instead.
1-1/4 in screws — USG lists 1-1/4 in Type W bugle-head screws complying with ASTM C1002 for its 1/2 in panels over wood framing. Coarse-thread screws are for wood studs; fine-thread self-tapping screws are for light-gauge steel studs.
Count the sheets for the walls and the ceiling separately, multiply by the screws per sheet and add about 10% for dropped and stripped screws. A 12 × 12 ft room takes 14 wall sheets × 28 + 5 ceiling sheets × 35 = 567 screws, 624 with 10% extra.
It depends on the screw length and gauge, so check the count printed on the box rather than a rule of thumb, and divide the total screws by it to get the number of boxes.
Hiring a crew instead? The drywall installation cost calculator prices hanging and finishing by finish level.
Need the whole roof at once? The free roofing calculator works out roof area, squares, shingle bundles, underlayment, drip edge, ridge cap and installed cost from one set of measurements.