Knowledge Hub
Independent damp and mould guides for UK homes.
Plain-English, evidence-led readings on what causes damp and mould in UK housing, what the law says, what drives the cost of repair, and what to do when a landlord isn't responding. Written for tenants, homeowners, landlords and housing professionals. Because Stop The Mould doesn't sell damp-proofing or removal treatments, the guides say what we see, not what we sell.
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Understand the problem
Diagnose what you're actually looking at.
The most common damp and mould problems in UK homes, with the tell-tale signs that distinguish each one from the others, and what to do first.
Problem guide
Why is there black mould on my walls, and what should I do?
Black spots on your walls? Learn how to tell condensation mould from penetrating damp, what to do first, and when you need a formal evidence report.
Problem guide
Why does condensation mould keep appearing in my bedroom?
Waking up to mould on the wall by your bed? Understand why bedrooms are worst hit, the real ventilation-vs-heating trade-off, and what to change first.
Problem guide
Why is there mould only behind my wardrobe?
Mould only appears behind a wardrobe pushed against an external wall. Here's exactly why, and why the '5cm rule' is more about physics than tidying.
Problem guide
There's a damp patch on my ceiling — is it a leak or condensation?
A brown ring on the ceiling doesn't always mean a leak. Use the shape, edge and timing to tell a plumbing leak, roof defect and condensation apart.
Problem guide
Why is there so much mould in my bathroom?
A black line on bathroom sealant is usually worn sealant. Mould in the ceiling corners usually means the room is not clearing its steam. How to tell which.
Problem guide
How can I tell if it's actually rising damp?
True rising damp is rarer than the damp-proofing industry says. Learn the real signs — tide marks, salts, the 1m rule — and how it's misdiagnosed.
Problem guide
How do I know if it's penetrating damp?
Damp on the inside of an external wall usually starts as a defect on the outside. Match interior clues to exterior causes — pointing, cills, driven rain.
Problem guide
Is my damp caused by a hidden leak?
Damp caused by a leak follows the pipe run, not the weather. Learn how to tell plumbing from appliance from external leaks — and how to trace before you tear out.
Problems
Black mould: what it may indicate (and what to do)
Plain-English guide to what black mould actually is, why it appears, how to read the pattern, and when to escalate.
Guides
When is a damp survey worth paying for?
A decision framework for when a UK damp survey is worth paying for: Free Case Check first, then a surveyor when structural, legal, mortgage or health triggers apply.
Your rights
What the law says, and how to use it.
The 2018 Homes (Fitness for Human Habitation) Act, Awaab's Law working-day windows for social tenants, and HHSRS damp-and-mould hazard categories, explained without legalese.
Rights & compliance
Tenant rights on damp and mould in England
Current England guidance for renters dealing with damp and mould: reporting in writing, Awaab's Law for social housing, private-renter routes and what to do if you are ignored.
Guides
Landlord obligations for damp and mould in rented homes
What UK landlords must do about damp and mould in 2025 — HHSRS, the Fitness for Human Habitation Act, Awaab's Law, and how to respond to tenant reports correctly.
Costs
What repair actually costs in the UK.
What drives the price of the fixes people are quoted most, from mould removal and damp surveys to extractor upgrades and chemical damp-proofing: what moves a quote, the cheaper-first alternatives, and the red flags. Written quotes, not published ranges.
Mould removal cost UK
What removal involves, when cleaning is enough, what moves the price and the red flags in remediation quotes.
Damp survey cost
A contractor's free visit, an independent surveyor or the Free Case Check: how the three compare and what drives the fee.
Condensation fix cost
Extractor fans, PIV units, trickle vents and humidistat controls: what moves the price and what is a sales pitch.
Cost to fix rising damp
Why rising damp is so often misdiagnosed, the cheaper-first checks and the red flags in damp-proofing quotes.
Bathroom extractor cost
Like-for-like swap versus a new duct run, humidistat versus basic, and what to ask an installer for in writing.
Mould cleaning cost
DIY versus professional cleaning, when cleaning is pointless because the cause remains, and how to compare quotes.
Awaab's Law
10 / 3 / 5 working days: what social landlords in England now have to do.
Since 27 October 2025, social landlords in England must respond to reports of damp and mould that present a significant risk of harm on a working-day clock: investigate within 10 working days, give the tenant a written summary within 3 working days of the investigation ending, and make the property safe within 5 working days of that. Emergency hazards must be dealt with within 24 hours. The guide covers how the clock works, what counts as a valid report, and what to do if a deadline is missed.
- 24 hours
- Deal with an emergency hazard.
- 10 working days
- Investigate the reported damp or mould, counted from the landlord becoming aware.
- 3 working days
- Give the tenant a written summary of the findings, after the investigation ends.
- 5 working days
- Make the property safe after a confirmed significant hazard, within 5 working days of the investigation ending.
Applies to social tenancies in England (Phase 1, from 27 October 2025).
Found mould? Don't just photograph it.
Stop The Mould helps you upload the right photos, get a clear first assessment, and organise your evidence, report, messages and follow-up in one place.
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