Timber decay and woodworm
The wall plate sits on the outer leaf and the felt beside it is wet. What has not been proved about the plate itself?
Not wet felt beside the wall plate proves the plate itself either rotten or sound. The plate is the timber on the outer leaf that takes the rafter feet. The felt next to it was wet, which is moisture beside the wood, not a probe through the wood. What has not been proved is the plate: its top, its seating on the leaf, and the face against the masonry. The survey records the wet felt beside it. It leaves the timber itself unproved.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
Felt gets wet from driven rain, a poor gutter or moisture under the tiles, and it can lie against a plate that is still firm or one that is already soft. Those cases are separated by testing the timber, not by reading the stain on the felt. A plate on an outer leaf sits in the weather zone, which is why the wet felt is worth naming. The location explains the concern. It is not a diagnosis of the wood.
Have the plate probed where it can be reached, and write down where it could not. If the felt is turned back in one bay only, the result belongs to that bay. Do not let a quotation renew the wall plate all round the house because felt was wet in the place described. Do not dry the felt in a photograph and call the timber finished either. The plate stays unproved until the wood has been tested.
What should you ask your surveyor?
- Which length of wall plate sits against the wet felt?
- Did you probe the plate itself, or only see the felt lying beside it?
- What part of the plate was out of reach on the day?
What are the typical next steps?
- Record the wet felt as beside the plate, not as decay already found in it.
- Ask a carpenter to probe the plate where it can actually be reached.
- Do not price a whole-roof wall plate from the wet felt alone.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Does wet underfelt mean the wall plate has rotted?
No. Wet felt is moisture beside the timber. It does not prove the plate has decayed, and it does not prove the plate is sound either.
Is the plate defective just because it sits on the outer leaf?
No. That position explains the exposure. It is not a condition grade. The plate itself was not proved, sound or rotten, on this visit.