Answers · What the work involves
What happens if my roof deck is rotten?
The short answer
Damaged sheathing is replaced sheet by sheet once the old roof is off, and it is the most common reason a roofing price changes mid-job. Agree the rate per sheet and an approval threshold in the contract, before the work starts, and ask to be shown and photographed what is being replaced.
Why it cannot be quoted exactly upfront
Nobody can see the deck under an intact roof. A contractor can infer from attic staining, from soft spots underfoot and from the roof's history, and they cannot know. That is genuine, and it is why a quote with a stated allowance and a stated rate is the honest form rather than a flat number that will change.
What to put in the contract
- A per-sheet or per-square-foot rate for replacement, agreed in advance.
- An allowance included in the quote, so small amounts do not become a change order.
- A threshold above which the contractor stops and gets your approval.
- A requirement to photograph what is replaced and where.
Also asked
- Is some deck replacement normal?
- On an older roof, yes — a few sheets around penetrations, valleys and eaves is routine. Whole-deck replacement is a different conversation and usually reflects long-term leaking or condensation, which should also be diagnosed rather than just covered over.
General information about roofs and about hiring, not advice about your building. Roofing contractor licensing, permits, insurance practice and deductible rules are set state by state and province by province across the United States and Canada, so your own authority is the current answer.