Cement Board (Tile Backer) Sheet and Screw Takeoff

sheets = ceil(area x (1 + waste) / sheet area), a 3x5 board being 15 sf; screws = sheets x per-sheet, roughly 30 to 40 corrosion-resistant backer screws at 8 in on center. A 120 sf tub surround at 10% waste is 9 sheets and about 315 screws; a 200 sf floor is 15 sheets. Add alkali-resistant mesh tape and thin-set at the joints (not counted) and set the board over a moisture barrier per the wet-area detail. Distinct from the gypsum drywall takeoff. A material-ordering estimate; ANSI A108 / the TCNA Handbook and the board manufacturer govern the fastener schedule and the wet-area assembly.

sheets = ceil(area_sf x (1 + waste_pct/100) / sheet_area_sf); screws = sheets x round(screws_per_sheet).

ANSI A108 / TCNA Handbook cement-board installation practice, by name; the board manufacturer governs the fastener schedule and wet-area assembly.

The takeoff arithmetic is public first-principles (area over sheet size); the ~30-40 screws per 3x5 sheet at 8 in o.c. and the wet-area detail come from the board manufacturer and ANSI A108 / TCNA.

Estimate. AHJ and licensed professional govern.

Field names used by the API: area_sf, sheet_area_sf, waste_pct, screws_per_sheet, sheets, screws

• Sheet size 3x5 ft = 15 sf, 3x4 ft = 12 sf; sheets = ceil(area x (1+waste) / sheet area)cement-board products
• Fastener schedule ~30-40 backer screws per 3x5 sheet at ~8 in o.c.; the board maker governsANSI A108 / TCNA Handbook