If we find rotten wood once your old roof is off, here's what happens. We photograph what we find and share the photos with you. You pay our actual cost, at a rate printed in your proposal before you sign. And extras can't go past $3,500 without your signature. The rest of this post explains how that works, what we can check before tear-off, and what we can't.
By Van Naik, owner · Updated September 24, 2026
Every homeowner has heard some version of the story. The crew shows up, the old roof comes off, and then the phone rings: "We found a problem." With no roof on the house and a dumpster full of shingles in the driveway, it's about the worst possible moment to negotiate.
So we settle how hidden damage is billed before the job starts, while you still have all the leverage.
What dry rot is
"Dry rot" is a bit of a misnomer. It's a fungus that breaks down wood, and it needs moisture to get started. It usually comes from one of two places:
- A slow leak. A cracked pipe boot or worn flashing lets a little water in every storm. By the time a stain shows up on your ceiling, the wood above it has often been wet for years.
- Poor ventilation. Moisture from showers, cooking and laundry rises into the attic, hits the cold underside of the roof deck and condenses there. Year after year, that softens the wood without a single leak.
Either way, rotten wood can't hold a nail. A new roof nailed into soft wood won't stay put, so it has to be fixed before the new roof goes on.
Expect some
We've been tearing off Bay Area roofs since 1989, and we expect most houses to have at least some dry rot. It usually shows up near valleys, along the lower edges above the gutters, and anywhere the attic couldn't breathe. Finding some is normal. It's also why we tell you the rate up front.
What we can check before tear-off, and what we can't
During the visit, we look for clues:
- Soft spots underfoot while walking the roof.
- Sagging along ridges or between rafters.
- The attic, where there's access: water stains, dark or delaminating wood, daylight where it shouldn't be.
- Your history. Where it has leaked before, and what's been patched. You know things about your house we don't.
Those clues tell us where to expect trouble. They can't tell us exactly how much. The top face of the deck is under the shingles, and the only way to see it all is to take them off. An exact dry rot number before tear-off is a guess, whoever gives it to you.
Does this apply to your house?
It depends on how your roof is built, so here's how the common types work:
- Plywood or OSB deck. Most homes built in the last several decades. We cut out the soft sections and put in new sheets.
- Plank deck. Common on older homes: solid boards laid side by side. We replace the boards that are soft.
- Skip sheathing. Boards spaced a few inches apart, common under wood shake, tile and metal roofs. Shingles need a solid surface, so if you're switching to shingles, we install new plywood over those boards. It's billed the same way as dry rot.
- Open-beam or exposed ceilings. If the underside of your roof deck is the ceiling you see from inside, replaced boards will show. We'll talk through that with you before the job starts.
What happens when we find it
1. We stop and photograph it. Before any wood comes out, we photograph what we found. If you're home, we'll show you in person so you can see and touch it.
2. We replace what the deck needs, and leave the rest. Every board that's too soft to hold a nail gets replaced. Sound wood stays, so you're not paying for work your roof doesn't need. In cities that inspect the deck, the inspector checks our work, and if the inspector asks for more, we replace it at the same rate.
3. It's billed at our actual cost. $300 per person per day, plus workers' comp and payroll tax, with lumber at what we paid for it. For a sense of scale: two people for a full day is $600 in labor, plus the comp and payroll tax, plus the plywood. It goes on a work order, and it shows up on your final invoice.
4. Past $3,500, you sign first. If extras reach $3,500, the crew stops, shows you what they found, and needs your signed approval before doing more. What that guarantees is that nothing big happens without you seeing it first.
The same rules apply to the other thing tear-off can uncover: a hidden second roof under the first one. That's billed at $50 per square, plus workers' comp and payroll tax.
Why billing at cost matters
We do not view hidden wood damage as a profit center. Because it's billed at cost, we're not looking for reasons to find it.
One homeowner described it this way on Yelp:
"The pricing was totally transparent. I knew exactly what would be fixed cost and what would be 'time and materials.'"
— Boris E., San Francisco
When you're comparing bids
Ask every roofer the same three questions: What's your rate for dry rot? Who approves extra work, and at what amount? Can I talk to a customer whose job had a change order? Put the answers side by side. Our full guide to comparing roofing quotes covers the rest.
Next step
If you'd like a better read on your deck before you commit, book a free visit. We'll walk the roof, check the attic if there's access, and tell you where we'd expect trouble. You can also ask us for a homeowner near you whose job had a change order, and call them before you decide.
Call (925) 381-9162.
About the author. Van Naik owns Affordable Roofing Systems, a family-owned roofer based in Contra Costa County and serving the Bay Area since 1989. If you've read older reviews that mention Kelly, Kelly is the previous owner. The crew in those reviews still does the work. CSLB #1145218 (C-39). Owens Corning Preferred Contractor and CertainTeed Master Craftsman.