Concerned about a property defect?
Worried about rot or woodworm in your timber?
Our RICS chartered building surveyors tell you whether the decay is active, what is actually causing it, and exactly how to put it right. Not every patch of rot or every old beetle hole needs treating, and we will tell you straight which ones do.
- Save time
- Avoid unnecessary costs
- Reduce stress
How to Tell If Your Timber Decay Is Serious
Timber problems turn up in almost every older property, and the great majority are either historic or easily dealt with once the cause is found. The difficulty is that a long dead woodworm infestation and a small patch of surface rot can look every bit as alarming as a live, spreading problem. They are not the same thing, and the right response to one is nothing like the right response to the other.
This guide explains what makes timber decay, which signs are worth acting on, and how a defect survey from our chartered building surveyors gives you a clear answer: is it active, how far has it gone, and what genuinely needs doing.
Decay needs damp
Sound, dry timber does not rot. Fungal decay and most wood boring insects need damp timber to take hold, which is why a timber problem is nearly always a moisture problem first. Track down the water getting in and deal with it, and you remove the very conditions the decay depends on. That single principle is why an independent survey so often saves money. The cure can turn out to be a repaired gutter rather than a houseful of chemical treatment.
Common types of timber decay
Wet rot
The most common form of fungal decay. It stays local to the damp timber that caused it, darkening and softening the wood, which often cracks along the grain and feels spongy underfoot or under a probe. Typical triggers are leaking gutters, penetrating damp, plumbing leaks and poorly ventilated floor voids. Wet rot does not spread into dry, sound timber, so once the moisture source is dealt with it usually stops in its tracks.
Dry rot
The form that earns timber decay its fearsome reputation. Despite the name it still needs damp to start, but dry rot (Serpula lacrymans) can then travel through damp plaster and masonry to reach fresh timber some distance from where it began. Tell tale signs include a rusty red spore dust, fine grey strands, cuboidal cracking that breaks the wood into cube like blocks, and a distinctive musty, mushroom smell. Because it spreads, dry rot needs identifying early and dealing with thoroughly.
Common furniture beetle (woodworm)
The usual cause of the small round holes most people call woodworm, roughly 1mm to 2mm across, with a fine powdery dust (frass) beneath them. The crucial question is whether the infestation is still active. Many holes are historic, left behind by beetles that died out years ago once the timber dried, and need no treatment at all.
Deathwatch beetle
A larger wood borer that favours older, damp hardwoods such as oak, leaving holes around 3mm across. It is found more often in period and historic buildings, and is usually linked to long standing damp rather than a recent problem.
Other wood boring insects
Less common species, including the house longhorn beetle and the powderpost beetle, attack particular timbers and can be more serious. Correct identification of the species matters, because it changes both the level of risk and the right response.
Moisture and ventilation, the cause behind the cause
Behind nearly every timber problem is water somewhere it should not be: a failed or bridged damp proof course, blocked sub floor air bricks, a long running leak, or condensation in an unventilated space. Diagnosing that source is the part that actually fixes the problem for good, rather than treating the symptom and watching it return.
Warning signs worth acting on
One of these on its own is not a diagnosis, but the more of them you can see, the more sense it makes to get the property looked at:
- Timber that feels soft, spongy or crumbles when pressed, where a screwdriver or bradawl sinks in easily.
- Darkened, discoloured or shrunken wood, sometimes cracked into cube like blocks.
- Fungal growth, fine strands or a rusty red dust on or near timber.
- A persistent musty or mushroom like smell in a room, cellar or floor void.
- Small round holes in timber with fine powdery dust collecting beneath them.
- Floors, stairs or skirtings that feel springy, bouncy or have started to sag.
- Damp patches or staining close to structural timber such as joists, lintels or window frames.
Unlike cracks, timber decay is not graded on a single numbered scale. What matters is whether the problem is active or historic, what is causing it, and how far it has spread. Establishing those three things is one of the first jobs a defect survey does, because a dead infestation or a dried out patch of rot often needs no treatment at all.
Not sure if your timber problem is live or long gone?
That is exactly the question a defect survey answers. Send us a few details and we will take a look.
What a defect survey for timber decay includes
The aim is to identify the cause, not just describe the symptom. When you instruct Price Lilford, you get:
- A detailed on site inspection of the affected timber and the areas around it, inside and out.
- Whether the decay or infestation is active or historic, identified rather than assumed.
- Identification of the type of rot or insect, with the level of risk explained in plain terms.
- The underlying moisture source traced, because that is what is driving the decay.
- Moisture readings and technical checks where they are relevant.
- Photographs of the affected areas.
- Recommended remedial options, in plain English.
- Guidance on who can carry out the work.
No jargon. No upselling. No confusion. We are RICS registered chartered surveyors and completely independent.
This matters more with timber than almost any other defect. A great many timber surveys are carried out by the same firms that go on to sell the treatment they recommend. Because we never do the remedial work and never work with contractors, we have no reason to recommend a single drop more chemical treatment than your property genuinely needs.
Why early investigation matters
Active decay rarely settles on its own, and timber problems tend to widen quietly behind skirtings and under floors. Catching it early helps you:
- Avoid escalating repair costs as decay spreads to sound timber.
- Prevent structural damage to floors, roofs and load bearing timber.
- Understand the risks before buying, if it is a property you are considering.
- Make confident, informed decisions about what to treat and what to leave.
A clear professional report also carries far more weight than a homeowner's description if you are selling, remortgaging or putting in an insurance claim.
Related problems we diagnose
Timber decay rarely sits in isolation, so it is worth ruling out the issues that so often travel with it:
- Damp and condensation: the moisture source behind nearly every case of rot and active woodworm.
- External walls and masonry problems: failed pointing, render and flashing let water reach embedded timber.
- Roofing and chimney issues: a leak up high frequently shows up as rot in the timber below.
- Cracks and structural movement: the same leaks and damp behind decay can sit behind movement too.
Frequently asked questions
Does all woodworm need treating?
No. A large proportion of the woodworm holes we see are historic, left by beetles that died out once the timber dried. Treatment is only worthwhile where the infestation is still active, which is one of the first things a survey establishes.
What is the difference between wet rot and dry rot?
Wet rot stays local to the damp timber that caused it and tends to stop once the moisture is dealt with. Dry rot can spread through damp masonry to reach fresh timber elsewhere in the building, which is why it is taken more seriously. They are treated very differently, so correct identification matters.
Is dry rot really as serious as people say?
It can be, because it spreads, but the panic around it often leads to far more treatment than the situation needs. Caught early and dealt with properly, dry rot is manageable. An independent diagnosis keeps the response proportionate to the actual problem.
Can timber decay be fixed without chemicals?
Very often, yes. Because decay depends on damp, fixing the moisture source and replacing any wood that has lost its strength deals with many cases on its own. Chemical treatment has its place, but it is not the automatic answer, and we will tell you when it genuinely is needed.
Do you carry out the treatment as well?
No. We are completely independent and do not carry out repairs or work with contractors. That means our advice is unbiased and focused solely on what is right for your property, not on selling you a course of treatment.
Will my insurance cover timber decay?
Usually not directly. Most buildings policies treat rot and woodworm as gradual deterioration or a maintenance matter rather than a one off insured event, so they are commonly excluded. Where the damp behind the decay was caused by something insured, such as an escape of water, a clear independent report helps you set out the link.
Get a clear answer on your property's timber
Request a defect survey and we will tell you whether the decay is active, what is causing it, and exactly how to put it right.
No jargon. No upselling. No confusion.