Timber decay and woodworm
How does wet rot relate to a leaking gutter, rather than to a missing damp-proof course?
Wet rot grows in timber that is staying wet. A leaking gutter soaking a fascia, a rafter foot or a window frame is a classic cause. A missing damp-proof course is about moisture at the bottom of a wall. The two meet only if that moisture is what is wetting this piece of timber.
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?
The Property Care Association’s wet-rot note describes timber that has been kept damp. The repair is to dry the timber and replace what is too far gone. Painting a soft fascia without fixing the gutter fails. Injecting a damp-proof course for a rotten bargeboard misses the gutter entirely.
Ask the surveyor which timber is wet and which defect is wetting it. Then ask a roofer or a joiner to price that piece of work. If the rot is in a joist end built into a wet wall, the wall and the joist are both in the brief. There is no national wet-rot price. Extent decides it, and extent may need opening up.
What should you ask your surveyor?
- Which leak is wetting this timber?
- Is the rot wet rot at a gutter, or are you worried about dry rot in the masonry?
- What can I see without opening up, and what can I not?
What are the typical next steps?
- Fix the gutter or the flashing in the same conversation as the rotten timber.
- Do not buy a damp-proof course for a fascia.
- Replace timber that has lost its strength. Do not rely on filler.
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
Can wet rot spread like dry rot through a dry wall?
Wet rot stays with the damp timber. If the wall is dry and the timber is dry, it stops. That is the practical distinction PCA draws. It is not permission to leave a leak.
Is a soft window cill always wet rot?
It is decay from moisture, often rain at the joint. The surveyor may not name the fungus. The repair is still the joint and the timber, not a chemical in the brickwork.