Independent damp surveys in Merton
Merton splits neatly in two along the Northern line. Wimbledon and its surrounds are Victorian and Edwardian; Morden and much of Mitcham were built in the decade after the tube arrived in 1926. The Wandle runs between them through what was industrial ground, and it affects the properties along it.
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Merton housing, and what it does when it gets wet
The Wimbledon stock is solid brick Victorian and Edwardian terrace and villa, much of it extended at the rear and converted in the loft. As across south west London, the productive defect is the junction between the original house and a later side return or rear extension: shallow flashings, low upstands and ponding outlets on flat roofs, showing up internally on a first floor wall well away from the entry point.
Morden and the interwar estates are cavity walled with functioning damp proof courses and airbricks under suspended timber floors. Damp there is almost invariably bridging: ground raised by successive drives and patios above the course, or blocked underfloor ventilation. Neither justifies the chemical injection that is regularly proposed for them.
Along the Wandle valley the ground is lower, historically industrial, and drainage is older. Made ground from former industrial use behaves unpredictably, and the original clay drainage under these streets is at the end of its life. A displaced drain under a solid floor gives persistent localised damp that no wall treatment will touch.
What we are usually called out to in Merton
- Flashings and upstands where a side return or rear extension meets original brickwork
- Ground raised above the damp proof course on interwar Morden and Mitcham stock
- Blocked airbricks and musty suspended timber ground floors
- Displaced and root damaged clay drains under solid floors along the valley
- Loft conversions that removed the roof ventilation path without replacing it
- Second opinions on injection quotes for cavity walled interwar houses
Getting the diagnosis right in a London building
London's housing has been altered more than most: basements dug, lofts converted, houses split into flats, gardens raised, chimneys removed. In Merton that means damp is frequently the result of a change made decades ago rather than of the original building, and the remedy is to undo or correct that change.
We look for those alterations as much as for the damp itself. A floor laid above an old course, a fan ducted into a void, a lightwell filled with decking or a stack capped without ventilation explains more damp than any failed damp proof course.
The inspection, around Wimbledon and across Merton
- Every wall showing damp, and the walls either side of it for comparison
- Rainwater goods and roof junctions from the ground and from windows, and closer where access is safe
- Basement and lower ground floors for water table, drainage and bridging at the lightwell
- Condensation risk measured with temperature and humidity readings
- Visible timber for decay and beetle, with moisture content recorded
- Anything that would need opening up, identified and agreed with you rather than done unannounced
What you receive
A written report with photographs within 24 hours, in plain English, that stands on its own whoever reads it.
- Findings by room and by elevation
- Readings and the pattern they form
- The diagnosis, and the causes considered and excluded
- Recommendations in priority order
- Notes for a purchase, a lease or a disrepair matter where relevant
- A clear line where a quote you hold for a Merton property goes further than the defect
How a survey is arranged
- Tell us the postcode, the property type and what has been noticed.
- We confirm the fee and the time. It does not change on the day.
- On site, outside first, then inside, with findings explained before we leave.
- The report arrives within a day, ready to forward to a solicitor, agent or freeholder.
We do not sell damp proofing, tanking, ventilation units or timber treatment. In Merton, as everywhere in London, that independence is what makes the report useful to a buyer negotiating a price, a tenant raising a disrepair issue, or an owner deciding whether a quote is justified.
Leaseholders, landlords and buyers in Merton
Leaseholders in Merton often discover that the cause of their damp sits in a part of the building they do not own. Our report says where the water is coming from and which element of the building it passes through, which is the evidence a freeholder or managing agent needs under the lease. For landlords, damp and mould are hazards under the Housing Health and Safety Rating System, and social landlords in England now work to the fixed timescales of Awaab's Law. Our guide to Awaab's Law explains what that means.
By town
Wimbledon
Large Victorian and Edwardian houses on the hill and in the village, terraces in South Wimbledon, many conversions. Valley gutters, basements and lower ground floors on slopes recur.
Mitcham and Morden
Interwar estates, including the large estates around Morden, and older housing around Mitcham. Drives, condensation and extension junctions are typical.
Colliers Wood and Raynes Park
Victorian terraces and interwar streets. Rear additions, yards and bays dominate.
Where we cover
We survey across the borough, from Wimbledon and Raynes Park through Mitcham to Morden and Colliers Wood.
- Wimbledon
- Raynes Park
- Morden
- Mitcham
- Colliers Wood
- Wimbledon Park
- South Wimbledon
- Motspur Park
- Pollards Hill
Postcode districts
- SW19
- SW20
- CR4
- SM4
What customers say about us
ATI came back to do additional works to my property and I can honestly say they are top notch. Tom was very pleasant and explained treatment required in detail. He worked quietly and made minimal distractions. Working area was left looking as good as new. Very happy.
Polly Cunningham, on Google
Tom and Ben were brilliant from start to finish. Friendly, professional, and really knew their stuff. The report was clear, honest, and sent over quickly. Highly recommend ATI Damp Surveying!
Gary Emberson, on Google
Merton questions
Why does damp show up on a wall nowhere near the leak?
Because water travels through a building along whatever path is available, and it only becomes visible when it reaches a surface it can wet. Entering at a roof junction, it may run along a joist, down a cavity or across a lintel before appearing on a wall a floor below and several feet sideways. That is why a survey that only examines the stained wall can tell you the wall is wet but not why. The diagnosis works backwards from the stain to the entry point.
Is a persistent damp patch on a solid floor always a rising problem?
No, and on this borough's older streets it is frequently a drain. Clay drainage laid a century ago cracks and displaces, particularly where there are mature trees or made ground, and a leak beneath a solid floor produces a localised damp patch that stays put and responds to nothing done to the walls. It is worth lifting the covers and checking the runs before anyone specifies a floor treatment over a live leak.
Our Wimbledon basement flat is damp. Does it need tanking?
It may need a below ground system, chosen after the water is understood. Drainage outside and the front area should be checked first.
Do interwar houses in Morden need damp proofing?
Rarely. Bridging by drives and patios is the usual cause of low level damp.
Do you survey near the River Wandle?
Yes. Low ground near the river can have a high water table, and the survey separates that from other causes.
Will you try to sell me damp proofing in Merton?
No. We carry out no remedial work, so there is nothing to sell after the survey. The report states the cause, the work that would actually fix it and an outline of what that work should reasonably cost, so you can get like for like quotes from contractors of your choice, or put it to a seller, landlord or freeholder.
Nearby
Book a damp survey in Merton
We survey and report only, with no treatment to sell, so what the report says is the whole of our interest. Same day response to every enquiry, and a written report with photographs within 24 hours of the visit.
Book a survey or call 020 3355 4944