Subfloor fastener schedule — 6 in at panel edges, 12 in in the field, plus glue
Fasten 6″ on center at the panel edges and 12″ in the field (IRC R602.3(1)): 2 edge joists × 9 + 5 field joists × 5 = 43 screws per 4×8 sheet. Run a continuous glue bead on every joist first — glue + screws is the APA squeak-free floor.
What this diagram shows
A plan view of one 4-by-8 subfloor sheet laid across seven joists at 16 inches on center, showing the IRC R602.3(1) fastener schedule. The two edge joists get fasteners 6 inches on center — nine per joist across the 48-inch sheet width — and the five field joists get fasteners 12 inches on center, five per joist. That totals two times nine plus five times five, or 43 screws per sheet. A continuous bead of adhesive runs on every joist before the sheet is set, because glue plus screws is the APA squeak-free floor system, not nails alone.
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OSB or plywood Sturd-I-Floor sheets, screws, ring-shank nails & AFG-01 adhesive — sized off your joist spacing per APA E30 and IRC R602.3. Free.
