Timber decay and woodworm

Why does the Property Care Association treat wet rot as a moisture problem first?

Because wet rot grows in timber that stays wet, and it stops when the timber dries and stays dry. The Association’s advice is to deal with the leak or the damp, then the damaged timber, not to sell a chemical as the repair. A survey that names wet rot should also say, if it can, where the water is coming from.

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?

Wet rot is local compared with dry rot. A window sill, a joist end under a leak, or a fascia behind a failed gutter are typical. The surveyor probes what they can reach. Soft timber under sound paint is easy to miss, and a firm result on one sill does not clear the others. The Association’s homeowner pages distinguish the look of wet rot from a general instruction to inject the walls.

Replacing the timber and leaving the gutter blocked will repeat the repair. Ask the surveyor which defect is feeding the rot. Price that defect separately from any timber splice. Costs vary with access, especially on a rotten lintel over a bay. Do not take a damp-proof course quote as the wet-rot repair.

What should you ask your surveyor?

Which timbers were soft, and which could you not probe?
What is letting the water in: gutter, sill, roof, or ground levels?
Would the rot stop if that source were removed and the timber dried?

What are the typical next steps?

Repair the water source before you replace decorative timber.
Do not fill a soft sill with filler and list it as repaired.
If a structural timber is soft, ask for it to be exposed properly before you rely on a price.

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

Is wet rot the same fungus as dry rot?

No. The Association describes them separately. Wet rot stays with the wet timber. Dry rot can spread further. The repair should match the one you have.

Will a dehumidifier cure wet rot?

It may help a room dry. It does not fix a gutter or replace a lintel that has already lost its strength.