How much should roof decking replacement cost?

Roof decking — the wooden panels beneath your shingles, usually 4x8-foot OSB or plywood — is one of the most common "surprise" line items on a roofing bill. You cannot see it until the old roof comes off, which is exactly why it should be settled before the job starts.

Decking replacement is typically priced per sheet. Nationwide, a reasonable installed rate runs roughly $75–$150 per 4x8 sheet (higher in high-cost metros), including the panel, fasteners, and labor. Some contractors charge closer to $50–$75 for the sheet alone plus labor; others bundle it into a flat per-square allowance. The key is that the rate is stated in the estimate, not discovered after the tear-off.

How much decking you actually need varies widely. A roof with no prior leaks may need zero to a few sheets; one with long-standing leaks, old solid-board decking, or multiple past layers can need dozens. A contractor who inspects the attic first can give you a better guess, but the final count is only known once the old roof is off.

Red flags: a quote with no decking allowance at all, or a per-sheet rate far above $150. Ask the contractor to cap the replacement at a set number of sheets and notify you if they find more.

QuoteVya flags whether your estimate includes a decking allowance — one of the most common items missing from low quotes.