Dry Rot, Wet Rot
& Woodworm
Timber decay is always a moisture problem first. We find and stop the water, then treat and repair the timber — in that order, because doing it the other way round simply buys time.
Dry Rot
Serpula lacrymans is the one that earns its reputation. It needs timber at around 20% moisture content or above to establish, but once established it can transport water through its own mycelium, spread across and through masonry, and attack timber some distance from the original wet area. That is what makes it different from every other decay fungus and why it cannot be dealt with piecemeal.
What it looks like: cuboidal cracking of the timber into brick-shaped chunks, a soft white cotton-wool mycelium, grey strands (rhizomorphs) running over masonry, rusty-red spore dust, and a distinctive damp mushroom smell. Often found in sub-floor voids, behind panelling, in basements and around chimney breasts and bay windows.
How we treat it: identify and eliminate the moisture source; expose the full extent of the outbreak, which is almost always larger than the visible damage; cut out affected timber back to sound material with a proper margin; sterilise and treat adjoining masonry where the fungus has run through it; introduce ventilation and, where needed, isolate new timber from masonry with DPC or support hangers; then reinstate. Where structural members are involved we replace with treated timber or steel to a specified detail.
Wet Rot
Far more common than dry rot and much more localised. Wet rot fungi — most often Coniophora puteana, the cellar fungus — need consistently wet timber, around 50% moisture content, and they do not spread beyond the wet area. That is the good news: fix the leak and the rot stops.
What it looks like: darkened, soft, spongy timber that crumbles when probed, longitudinal cracking, and frequently a distinct boundary where the wet zone ends. Typical locations are window sills and frames, door thresholds, the ends of floor joists built into external walls, cellar timbers and anywhere near a long-running leak.
How we treat it: stop the water, dry the area, cut out and replace decayed timber, treat the remaining sound timber with a preservative, and improve ventilation where the timber will stay at risk. It is often a smaller job than people fear once the source is identified.
Before you accept a quote for "full timber treatment"
Blanket spray treatment of an entire roof or floor is rarely necessary and is sometimes proposed because it is easy to price and quick to apply. Targeted treatment of affected and at-risk timber, combined with fixing the moisture cause and improving ventilation, is both more effective and usually cheaper. Ask any contractor which species they have identified and what evidence they have of active infestation. If the answer is vague, get a second opinion.
Woodworm
"Woodworm" covers several wood-boring beetles. In London property the overwhelming majority of what we see is common furniture beetle (Anobium punctatum) — 1–2mm round exit holes, gritty lemon-shaped frass — and a great deal of it is historic and inactive. House longhorn beetle and deathwatch beetle are far less common but far more serious, and they are treated differently.
The first question is always whether the infestation is active. Fresh, sharp-edged, light-coloured exit holes with clean frass below suggest current activity; dulled, dust-filled holes with no fresh frass usually mean an old infestation that died out when the timber dried. We survey rather than assume, because the difference is the difference between a targeted treatment and no treatment at all.
Where treatment is needed we apply a targeted insecticidal treatment to affected and at-risk timber, replace structurally compromised members, and — again — deal with the moisture conditions that let the beetles establish, since dry timber below about 12% moisture content is a poor host.
Structural Timber Repair
Where decay has gone beyond treatment we carry out the repair rather than handing you on to someone else: joist end replacement and resin repairs, new bearers and plates, lintel replacement, sub-floor ventilation improvements, and reinstatement of floors and joinery. Because we are part of a property repairs business, the timber repair, the damp cause and the making good are one job with one point of responsibility.
Timber TreatmentFAQs
Fresh exit holes are pale inside with sharp edges, and there will be clean, gritty frass on surfaces below. Old holes are dark, dull and often full of dust or paint. Adult beetles emerge between roughly May and September, so that is when activity is most visible. The reliable test is a survey — a lot of properties are treated for infestations that died out decades ago when the roof was fixed.
Not necessarily, but it does mean a thorough opening-up inspection, because the visible damage is reliably the smaller part of the outbreak. What we will not do is treat what can be seen and leave the rest, since dry rot carries its own moisture and will keep going. The survey establishes the extent first, so the scope of works is based on what is actually there.
The products we use are HSE-approved and applied by trained operatives under controlled conditions. There is a re-entry period after application — usually a matter of hours, and stated in writing before we start — and we agree access arrangements with you in advance. Where a property is occupied by young children, pets or anyone with a respiratory condition, tell us and we will specify accordingly.
Often, yes — particularly where a homebuyer's survey has flagged damp or timber concerns, or in older property with a cellar or suspended timber floors. A damp and timber report from a specialist, with a guarantee where works have been done, is normally what the lender is asking for. We can usually survey and report inside a week.
Get the Cause Found & Fixed
Book a survey and you get a written report: what is causing the damp, what it takes to fix it and what it costs. No pressure, no guesswork.
Survey fee deducted from the cost of works if you proceed