Subfloor Calculator
Sheets are 4×8 ft (32 sq ft). Fastening follows the joists, so screw count depends on joist spacing.
How this calculator works
- Sheets = area × 1.1 ÷ 32 sq ft.
- Screws follow APA nailing guidance: about 6 in on panel edges and 12 in in the field, so each joist crossing gets five fasteners.
- One 28 oz tube lays roughly 50 linear ft of 1/4 in adhesive bead.
Subfloor questions
Plywood or OSB for subfloor?
Both are approved when the panel carries an APA Sturd-I-Floor or rated-subfloor stamp. Plywood recovers better if it gets wet during a build; OSB is usually cheaper and more uniform.
What thickness subfloor do I need?
23/32 inch (sold as 3/4) is standard for joists at 16 or 19.2 inches on center. Tile often needs an extra underlayment layer to meet deflection limits.