Roof Rot: What It Means and What to Get in Writing

Updated 2026-10-24 · Sources checked

"Why would I be on the hook for dry rot?"

A commenter in a roofing thread about changing companies asked that. Roof rot is wood that stayed wet long enough to decay, and rotted boards get replaced. In a full replacement, the old roofing comes off and any damaged wood is replaced¹. The part to settle before you sign is the number of boards the roofer counts and how any extra ones are priced and approved.

Quick answer:

Ask the roofer to photograph each rotted board where it sits, before it goes in the dumpster.
Ask for the price of replaced wood and a signed change order in writing before any extra work.
Read your policy's wording on wear and tear before you count on insurance, because a standard policy will not pay for damage caused by routine wear and tear².

On this page

What is roof rot, and does it mean a new roof?
Why the wood stays wet
Who is on the hook for rotted wood?
What a contract should say about hidden wood
Steps before you sign
Checklist before you ask for quotes
Quick questions

If the wood is not exposed yet, you can set the ground rules for it before any work begins. If the roof is already open, the same rules apply to any extra boards the roofer asks you to approve.

What is roof rot, and does it mean a new roof?

Roof rot is decay in the roof decking: the boards or plywood sheets the shingles are nailed to. It needs wetness, because wood saturated with water (about 30% moisture) will rot, and below 20% moisture these fungi will not grow³.

So the rotted boards get replaced, and whatever kept them wet gets dealt with. Whether the rot means you have to replace the whole roof or only the damaged wood is something to ask each roofer, not to assume. Ask for two prices, the rotted section alone and a full replacement, and for the reason they recommend one. A full replacement already includes the wood step, which is why the wording of your contract matters more than the word "rot".

Why the wood stays wet

Water that keeps reaching the same wood. A hole or missing shingles can let it in, and a drip trail or a spot of light coming through in the attic shows where to look⁴.

Once it is thrown out, rotted wood is hard to judge. As one commenter in a roofing thread put it: "Dry rot isn’t really gonna look like much sitting in a dumpster. But walking on it you will feel it"

Who is on the hook for rotted wood?

It depends on your own policy and on what caused the rot. In Texas, insurance companies won't pay for damages that happen over time, like rotted boards or worn roofs⁵, so do not assume a claim will be paid.

If you are thinking of filing a claim, ask your insurer who inspects and which repair it would accept before the work starts.

If extra wood adds to the bill, how would you cover it? How to pay for a new roof without enough saved.

What a contract should say about hidden wood

Hidden wood is a known surprise on paper. Treat rotted decking as a change-order item. In Oklahoma, rotted decking is an example of an "unforeseen field condition"⁶, a hidden problem that can add work and cost, and a change order is the written form that records the change.

In California, a change to the price or the work must be in a written change order, signed by the customer and the contractor before the change⁷.

A vague line leaves the price open. One commenter described the wording in their own contract: "Our contract says “Inspect the deck for rot and imperfections. Change as necessary.”" It names no price and no limit on the number of boards.

Want to see what else a replacement quote should list besides the wood? What is included in a roof replacement.

Steps before you sign

If you may file a claim, ask your insurer the questions above before the work starts.
Get multiple written estimates; each should describe the work, materials, completion date and price⁸.
Lay the estimates side by side and read the wood lines first.

Got quotes that price the wood differently? How to compare roof estimates when the totals don't match.

Checklist before you ask for quotes

Have these ready before you compare what each roofer offers.

Your policy's wording on routine wear and tear², if you may claim.
A price for each sheet or board of replaced wood, or a cap on what extra wood can add.
A change order you sign before any extra wood is replaced.
The payment schedule, showing what you pay at each stage.

Ask each roofer to put the last three in writing. You can send this:

Please write in the estimate the price per sheet for replacing rotted decking, and how much extra wood can add before you stop and get my signed change order. Please also send photos of each board you replace, and do not replace any extra board until I have approved it in writing.

If a roofer pushes you to sign today or won't price the wood separately, that is an answer too: weigh it against the bids that do.

Quick questions

How much does it cost to replace rotted wood on a roof?

It depends on the number of boards the roofer finds under the old roofing, and nobody can count them until it comes off. Ask each roofer to say how many boards they expect to replace and how they would handle any beyond that.

How can I get my roof repaired if I have no money?

Ask each roofer for two prices, one for the dry rot repairs alone and one for a full replacement. Then you can see what each option would cost you, and when.

Can roof rot happen without a leak?

Yes. Repeated or long-lasting condensation in an attic or roof can cause serious damage to the wood, including rot, swelling and delamination⁹, which is plywood layers coming apart. Ask the roofer whether the rot looks like a leak or like attic moisture.

What is the 25% rule for roofing?

In Florida, the code limits repair, replacement or recovery to 25 percent of a roof or roof section in any 12-month period unless the whole roofing system or section is replaced to meet the code¹⁰. For a Florida roof or section built, repaired or replaced under the 2007 Florida Building Code or a later edition, only the repaired, replaced or recovered portion¹¹ has to meet the current code. Wherever you live, ask the roofer and your local building department whether a rule like it applies to your repair.