How is roof decking cost figured per square foot?
Short answer. Roof decking is almost always priced per sheet, and a standard 4 by 8 sheet covers 32 square feet, so per square foot pricing is mostly a conversion. Most roofs need only a few sheets replaced, but leaks, poor ventilation or old plank decking can turn that into a large line item, so get the per sheet price in writing before work starts.
Why per sheet
Decking problems show up in patches: around a leaking pipe boot, along a valley, at the eaves above a clogged gutter. The crew pulls the damaged sheets and installs new ones, so the natural unit is the sheet. The price per sheet includes the material, the extra tear-out, and the labor to fit and nail it.
How much is normal
- Healthy roof, good ventilation: often zero to a few sheets.
- Past leaks or a hot, damp attic: more, concentrated where water or moisture sat.
- Plank decking with wide gaps: sometimes a full re-sheet over the entire roof, which is quoted as its own line.
Thickness and type
The new sheathing has to match the rafter spacing and the existing deck, so the roof stays flat. OSB and plywood both work when rated correctly; see OSB vs plywood roof decking.
Protect yourself in the contract
- Get the per sheet price in writing.
- Ask the crew to photograph damaged decking before replacing it.
- Ask for the sheet count on the final invoice.
When insurance may pay
If a covered storm loss requires replacing decking, or code requires re-sheeting over spaced boards, coverage depends on your policy, including any ordinance or law coverage. See code upgrades and ordinance or law coverage.