What is the cost to replace roof decking during a roof replacement?
Short answer. Most roofers price decking replacement per 4 by 8 foot sheet, written into the contract as a unit price that applies to however many sheets turn out to be bad once the old shingles are off. On many North Georgia reroofs only a handful of sheets need replacing, so the line is often small, but get the per-sheet price in writing before tear-off.
Why it is a unit price
Nobody can see the decking until the shingles and underlayment come off. Rather than guess, a fair contract states a price per sheet and sometimes an allowance, so you pay for what is actually replaced.
What the per-sheet price should include
- Cutting out and removing the damaged sheet.
- The new panel, matched to the existing thickness.
- Fastening to the rafters or trusses with proper spacing.
- Disposal.
Where bad sheets usually turn up
- Along the eaves, where clogged gutters or missing drip edge kept the edge wet.
- Around chimneys, skylights and pipe boots with old leaks.
- In valleys, which carry the most water.
- Under spots where the attic shows staining.
How to verify the count
- Ask for photos of each damaged area before and after replacement.
- Ask the crew to set aside removed sheets if you want to see them.
- Compare the count to any attic staining you noticed beforehand.
Red flags
A contract that says decking will be replaced "as needed" with no price, a sheet count far higher than the visible problem areas with no photos, or pressure to approve a big number by phone during tear-off without seeing it.
On insurance jobs
Decking that must be replaced to install the new roof is often added after tear-off as a supplement, backed by photos and measurements. See OSB vs plywood roof decking and what to expect on roof replacement day.