Damp in London Flats: A Silent, Ongoing Problem
Whether you live in Hackney, Camden, Southwark or Islington, one thing’s clear: damp in London flats is a widespread issue — even in newly decorated or recently converted homes.
Many flat owners and tenants complain of:
Persistent musty smells
Black mould forming behind wardrobes or on ceilings
Condensation around windows
Damp walls despite ventilation
If you’ve tried opening windows, dehumidifiers, and mould cleaner — but the damp keeps returning — you may be dealing with deeper structural causes that only a professional damp survey can uncover.
Why Converted Properties Are So Vulnerable to Damp
Many flats in London are created by converting older properties — especially Victorian and Edwardian terraced homes.
These buildings weren’t designed to be split into multiple self-contained units. The conversion process can unintentionally trap moisture or interrupt ventilation pathways.
Here are the hidden causes we commonly find during our damp surveys in converted flats across London:
1. Bridging Between Flats
In converted buildings, walls and floors often create thermal bridges — cold spots where moisture condenses. Damp can migrate from the flat below or adjacent units, especially if there’s:
Rising damp in the lower unit
Plumbing leaks
Poor damp-proofing during conversion
2. Blocked Ventilation Routes
Original chimney stacks, subfloor vents, and air bricks are often blocked off during refurbishment. This leads to trapped, humid air, especially in:
Kitchens without extractor fans
Bathrooms with no mechanical ventilation
Flats with sealed windows or poor airflow
3. Condensation Buildup
If you're living on a top floor, heat loss through the roof and external walls increases surface condensation. Pair that with daily moisture from cooking, drying clothes, and showers — and you’ve got a recipe for black mould.
4. Poor Insulation During Conversion
Many flats were converted decades ago, before strict insulation standards. Cold external walls and single-glazed windows act as condensation magnets.
5. Leaky Roofs or Gutters (from Above)
Water ingress from communal roof areas often goes unnoticed — especially if there’s no roof access or ongoing management. We've seen numerous cases of penetrating damp from cracked flashings or overflowing gutters above flats in boroughs like Camden and Lewisham.
Why You Need a Professional Damp Survey — Not Just a Dehumidifier
Temporary fixes like fans and dehumidifiers treat the symptom, not the cause.
A professional damp survey in London gives you:
A full inspection of internal and external factors
Moisture readings using specialist equipment
Diagnosis of the type of damp (condensation, rising, or penetrating)
Identification of hidden bridging points, insulation gaps, or poor ventilation
A clear report with next steps tailored to your flat
We’ve surveyed countless flats where the damp issue came from a neighbouring unit, blocked air vents, or poor conversion work — things you won’t see without the right tools.
Real Case: Persistent Damp in a Top Floor Flat in Peckham
A client in Peckham contacted us after repainting their bedroom three times in a year. Mould kept forming in the same spot.
Our survey revealed:
Warm, moist air rising from the kitchen
No ventilation in the en-suite
Cold bridging in the roof eaves
Trapped air behind large fitted wardrobes against an external wall
Our report led to better ventilation installation and minor insulation works — ending years of frustration.
Living in a London Flat? Here’s What to Do Next
If your flat has ongoing damp — or if you're a landlord receiving tenant complaints — don’t rely on guesswork.
Book a professional damp survey and get a full breakdown of what's causing the issue and how to solve it.
We cover:
Hackney
Camden
Islington
Lewisham
Southwark …and all of Greater London.
Book Your Damp Survey Today
Don’t wait for black mould to spread or tenants to escalate. A small investment in a damp survey today could prevent thousands in repair costs tomorrow.
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