Home / Guides / Woodworm and rot: what a treatment quote should look like
Woodworm and rot treatment: what the quote should say, and when to refuse it
Most of the timber quotes we are asked to review are for work the building does not need. That is not because contractors are dishonest; it is because the person setting the scope is usually the person paid to carry it out, and timber gives them a defensible reason for almost any scope. This page is written for the person holding such a quote: what it has to establish before the figure means anything, what the work typically costs when it is warranted, and the cases where the correct response is no.
Why two quotes for one outbreak differ by a factor of four
Because the scope is a judgement rather than a measurement. Dry rot can travel through masonry, so a cautious contractor can justify opening up a great deal. Woodworm leaves holes for a century after it has died, so a blanket treatment of every timber in the house can be presented as prudent. Neither scope is dishonest on its face, and neither is checkable from the quote itself, which is why an independent determination of what is actually there converts a judgement into a documented finding that both figures can be measured against.
The four things a quote must establish
Whether the activity is current or historic, with the evidence: fresh frass, the condition of the flight holes, the moisture content of the timber. Which organism it is, because deathwatch beetle in Georgian oak, furniture beetle in a Victorian floorboard, wet rot at a bay and dry rot behind a dry lined wall are four different problems with four different price tags. The extent, with a basis for it rather than an assumption. And the water: what is wetting the timber, and whether the quote proposes to stop it.
A quote missing any of the four is incomplete whatever it costs. A quote missing the last one is a certificate with a price on it, because fungal decay and beetle both depend on moisture, and treatment applied over a live source fails.
What the work typically costs when it is warranted
These are the ranges we see quoted across London for work that is actually justified, and they are for orientation rather than for pricing your job. A localised wet rot repair, a joist end, a sill, a section of floor, is carpentry and normally sits in the low hundreds to around a thousand pounds. A targeted treatment of an affected roof or floor section for active woodworm, after the moisture is dealt with, is typically a few hundred to the low thousands. A confirmed dry rot outbreak with opening up, replacement and masonry treatment begins in the low thousands and can reach five figures in a house where it has run behind plaster for years.
Two figures should raise a question rather than settle one. A blanket woodworm treatment of the whole house, usually between one and three thousand pounds, is the quote we are most often shown and least often able to justify. And any dry rot figure that arrives without a stated extent is a figure for the scope the contractor has chosen, not for the outbreak.
When to refuse it
Refuse treatment of historic woodworm: dark, dusty holes with no fresh frass in timber that reads dry. Refuse a whole floor or whole house scope offered on the strength of one soft joist end. Refuse any treatment that does not name the water source and include stopping it. Refuse a guarantee on chemical treatment as a substitute for replacing timber that has lost its strength, because no chemical restores section. And treat a quote that says the work is urgent with the scepticism a slow organism deserves.
In each of these cases what the building needs is a repair, a repair to the water, or nothing. ATi carries out no treatment, tenders for nothing and recommends no contractors, so a report that says none of this work is required costs us exactly nothing to write, and we write it often.
Purchases, lenders and retentions
Timber is one of the most common reasons a lender holds back part of a mortgage advance in London, because a valuation records flight holes and refers the matter on without deciding whether the infestation is alive. The retention is released against a specialist report, and where that report establishes that the activity is historic there is nothing further to do. For a buyer, the same report is the basis for a renegotiation with a number on it rather than an open worry, and it costs a small fraction of the treatment the valuation implied.
Questions
The seller has a twenty year timber guarantee. Does that settle it?
It settles very little. A guarantee covers the treatment that was applied, on the terms the treating firm wrote, and it depends on that firm still existing. It does not establish whether the treatment was needed, whether the water source was ever dealt with, or whether decay is present now in timber the treatment never reached. An independent inspection of the timber as it stands today is what a buyer or a lender can actually rely on.
Can I ask the seller to pay for the survey?
You can ask, and it is sometimes agreed where the valuation raised the issue, but the more useful lever is the report itself. A finding of active decay with a scoped figure attached is something your solicitor can put to the seller as a price reduction. A finding that the activity is historic removes the retention and the worry at once, which is worth more than the fee whoever pays it.
We are leaseholders and the rot is in a shared floor. Who pays?
Usually whoever is responsible for the water that caused it under the lease, which is a question of fact before it is a question of law. A report that identifies the source, a failed gutter, a leaking flat above, a bridged damp proof course in a communal wall, is what allocates the cost, and it needs to have been written by someone with no interest in the answer. That is the case we are most often instructed on by managing agents and solicitors.