Wet Rot Treatment
Wet rot is the most common form of timber decay in UK homes. It stays where the damp is, so the lasting fix is always the same: stop the moisture, treat the decay and repair the timber properly, all backed by a written guarantee.
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What is Wet Rot?
Wet rot is fungal decay of timber caused by sustained dampness. It is not one fungus but a group of them, the most common being Coniophora puteana, the cellar fungus. It needs wetter conditions than dry rot to take hold, and it is by far the most common form of timber decay in UK properties.
It comes in two broad types. Brown rot leaves timber dark, almost scorched looking, cracking along and across the grain and crumbling when dry. White rot leaves timber bleached, soft, spongy and stringy. Both weaken the wood, and both are a sign that something nearby is letting in or holding water.
Crucially, unlike dry rot, wet rot stays confined to the damp timber itself. It does not march through masonry to reach dry wood elsewhere, which makes it more contained, though it is often hidden beneath a thin, sound looking or painted surface, so the damage can be worse than it first appears.
Signs of Wet Rot
Wet rot turns up wherever water lingers, around windows, under floors, near leaks and in damp cellars. Look out for these signs.
Darkened, Cracked Timber
With brown rot the wood turns dark, almost scorched looking, and cracks into blocks before crumbling. A classic sign of the cellar fungus.
Bleached, Spongy Wood
With white rot the timber lightens, going soft, stringy and fibrous to the touch rather than darkening.
Soft Wood That Gives
Decayed timber feels soft and spongy and a screwdriver pushes in easily, where sound wood would resist.
A Sound-Looking Surface
Wet rot often hides under a thin skin of healthy wood or intact paint, so a frame can look fine yet be decayed underneath.
Dark Fern-Like Strands
Fine brown, grey or black thread like strands on the surface, typical of Coniophora, staying close to the damp area.
A Damp, Musty Smell
An earthy, musty odour around a window, floor or cellar is often the first hint of decay before anything is visible.
Wet Rot or Dry Rot?
Wet rot is far more common than dry rot, and the good news is it is usually more contained. It stays in the wet timber and cannot travel through masonry, so once the damp is fixed it tends to stop in its tracks.
The two are easily mistaken for one another, though, and the treatment differs. Just as importantly, timber left wet for long enough can eventually invite dry rot, the far more invasive problem, so wet rot is not something to leave. Getting the diagnosis right, and acting on it, is what keeps a small job small.
Our approach: we confirm which type of decay is present and what is causing the damp before recommending anything, so the work matches the actual problem.
What Causes Wet Rot
Wet rot is always a moisture problem first. Common sources include:
How We Treat Wet Rot
Survey and diagnosis
We confirm it is wet rot rather than dry rot, identify the moisture source and check how much timber is affected, including decay hidden beneath sound looking surfaces.
Fix the cause first
We stop the water at source, whether that is a leak, penetrating damp, rising damp or condensation, because without this the rot will simply return.
Dry the timber
The affected area is allowed to dry, removing the conditions wet rot needs to keep growing.
Remove and repair
Badly decayed timber is cut back to sound wood and replaced. Where suitable, sound joinery such as window frames can be repaired with resin rather than fully replaced.
Treat and protect
Remaining and new timber is treated with preservative and, where helpful, ventilation is improved to keep the area dry for good.
Written guarantee
Completed work is backed by a written 10 year guarantee, transferable on sale and accepted by solicitors and lenders.
Why It Pays to Act Early
Wet rot is very treatable, especially when it is caught before the timber loses its strength. Acting early keeps the job contained.
What Our Customers Say
Genuine reviews from Advanced Damp customers.
"Michael was an incredible support during a very stressful period. He provided a thorough, fair, and honest assessment, and his use of modern testing and technology ensured everything was measured accurately. Thanks to him, we now have a clear and reasonable remediation plan."
"Professional company and a great transformation. The area is a small below ground void that has a sloped cement retaining slab. They damproofed it and then came up with a great plan to add storage shelves. It looks great and has added the storage that we wanted."
"Lionel came to survey our flat. He couldn't have been pleasanter or more professional. He explained all his findings and we're hoping we're now on the way to resolving our mould problems."
Related Timber & Damp Services
Wet rot is a moisture problem at heart, so it often sits alongside these related services:
Wet Rot FAQs
What is wet rot?
What is the difference between wet rot and dry rot?
Is wet rot dangerous?
Will wet rot spread?
What causes wet rot?
How do you treat wet rot?
Think You Have Wet Rot?
Book a survey and get a clear, written diagnosis of what is really going on, the cause behind it and exactly what needs to be done, with no scare tactics.
Last updated June 2026 · Advanced Damp Ltd · Wet rot treatment nationwide · 0300 373 7251