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Wet rot, damp and woodworm across London

Wet rot treatment in London
starts with
finding the water.

Most damp money in London is spent on the symptom. Chemical injections and replastering do nothing at all if the water is arriving from a gutter, a raised path or a failed seal.

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Three different problems

Damp is not one
condition.

Rising damp comes up from the ground through the wall by capillary action, and it should be stopped by a damp proof course.

The things that get missed

Look outside
before you look inside.

Before anyone injects a wall, the external causes are worth ruling out because they are cheaper and far more common. A downpipe discharging onto the ground next to the wall.

Rot and woodworm

Timber decay follows
the water in.

Wet rot is the common one. Timber gets and stays wet, fungus takes hold, and the timber goes soft, dark and stringy.

Wet rot in London homes

Where wet rot
actually turns up.

Wet rot needs timber that stays wet, and in London housing that means the same few places every time: fascia and soffit boards behind a gutter that has been overflowing, window sills and the bottom rails of timber frames, external door thresholds, and the ends of floor joists sitting in a damp wall over a sub floor with blocked air bricks.

If a survey flagged it

What your report
probably said.

Reports are cautious about damp because moisture meters give readings, not diagnoses. Typical wording is elevated moisture readings were recorded, further investigation by a specialist contractor is recommended, and no guarantee documentation was available for previous damp proofing works.

Common questions

Questions we get
asked most.

Is rising damp as common as damp companies say?+
No. True rising damp exists but it is diagnosed far more often than it occurs. Penetrating damp from an external defect and condensation account for a large share of what gets treated as rising damp, and neither is fixed by injecting a wall.
How do I tell condensation from penetrating damp?+
Condensation shows as black mould, typically in corners, behind furniture and around cold reveals, and it is worse in winter and in rooms that are heated intermittently. Penetrating damp is a patch on the wall that corresponds to weather from one direction and gets worse during and after rain.
Is woodworm always a problem?+
No. The question is whether it is active. Fresh, clean edged holes with fine dust beneath suggest current activity. Darkened holes with no dust are usually historic infestation that has long since died out, and treating them is spending money on nothing.
What is the difference between wet rot and dry rot?+
Wet rot stays where the water is and stops once you fix the source and replace the timber. Dry rot can spread through masonry to reach new timber well beyond the original damp area, so it needs identifying properly and treating more widely.
Why do you want to look outside first?+
Because most internal damp is caused by something external and cheap to fix: a leaking gutter, a raised path bridging the damp proof course, eroded pointing, or a blocked air brick. Treating the inside without fixing those produces the same wall again within two years.
How do I know if it is wet rot?+
Press it. Wet rot timber is soft, darker than the surrounding wood, and breaks into stringy or cube shaped pieces, and paint over it blisters.
Can wet rot be fixed without replacing the timber?+
Only if it is caught very early and the timber is still sound, in which case drying it out and treating it can be enough.
My survey says timber decay is suspected behind the guttering. What does that mean?+
The surveyor could not see behind the gutter but expects the fascia or soffit boards there to be rotting, because an overflowing gutter keeps that timber wet. It is one of the most common lines in a London survey. The fix is to repair the timber and sort the gutter in the same visit.
Do you treat dry rot as well as wet rot?+
Yes. Dry rot needs a wider opening up and treatment of the masonry it has passed through, but the starting point is the same: stop the water.
Do you cover north London?+
Yes, including Finchley, North Finchley, Edgware, Wood Green and Haringey, as well as south and west London.
Tell us what it says

Get a written
price.

Quicker to ring
07498 597339

Monday to Saturday 9am to 8pm, Sunday 9am to 3pm. All London boroughs.

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Or email
enquiry@gmasgroup.co.uk

Send the paragraph from your report and we will price the work it describes.

How wet rot is treated

Stop the water, then repair the timber.

Find and stop the water

Wet rot only grows in timber that stays wet. The leak, overflowing gutter, failed seal or bridged damp proof course is repaired first.

Open up and assess

Floorboards, skirtings or joinery are opened up so the full extent of the decay can be seen and probed.

Cut out and replace

Decayed timber is cut back to sound wood and replaced with treated timber, with structural members supported while the work is done.

Treat what stays

Retained timber near the affected area is treated where it is appropriate, and new timber is kept off damp masonry.

Make good

Floors, skirtings, plaster and decoration are reinstated, and you are told what to keep an eye on afterwards.

Dry rot

Dry rot treatment and repair.

How dry rot differs

Dry rot can spread through masonry to reach dry timber, so it is opened up further than wet rot. Look for white cotton wool growth, orange spore dust and timber that cracks into cubes.

What the repair involves

The moisture source is fixed, affected timber is cut out well beyond the visible decay, the masonry is treated where the growth has passed through it, and new treated timber is fitted clear of damp walls.

Across London

Wet and dry rot in north and south London.

North London

We treat wet and dry rot in Finchley, North Finchley, Edgware, Wood Green and across Haringey, where suspended timber floors in 1930s and Edwardian houses often decay after a blocked air brick or a leaking pipe.

South London

In south London Victorian terraces, the usual culprits are rotten window sills, joist ends in damp walls and timber under a bay that has been leaking for years.

Damp proofing

If the problem is damp in the walls rather than rot in the timber, see our damp and mould page for diagnosis and damp proofing.

Related work

Often needed
alongside this.

Gutters, fascias and soffitsClearance, repair and replacement, including box and valley gutters.Read moreMisted glazing and gutter repairFailed double glazing units and leaking or overflowing gutters put right.Read moreDrain survey and repairCCTV survey with footage and report, then lining or excavation and making good.Read moreRepointingCrumbling mortar raked out and repointed in the right mix for the brick.Read more
Coverage

Areas we cover.

We take damp and timber treatment work across all 32 London boroughs. Most of our work is in west London, in Shepherd's Bush, Hammersmith, Fulham, Kensington, Chiswick and White City, and in south west London, in Putney, Wandsworth and Wimbledon. We also work in south east London, in Greenwich, Blackheath and Lewisham.

If your property is outside these areas, call us anyway. We travel across London and will tell you honestly if a job is too far to price properly.

Shepherd's BushHammersmithFulhamKensingtonChelseaChiswickWhite CityNotting HillActonEalingPaddingtonEarl's CourtSouthallUxbridgeHounslowBrentfordHarrowWembleyPutneyWandsworthWimbledon and all other London boroughs
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