Help and Advice
Expert Guides
Practical, jargon-free guides on identifying, treating and preventing damp — written by London specialists with over 15 years in the field.
Common Damp Questions
Straight answers to the questions we hear most — no filler.
How do you treat damp walls internally?
Fix the moisture source first. Remove all damaged plaster, apply a damp proof membrane to bare masonry, then re-plaster with moisture-resistant sand-cement or specialist renovation plaster. Never plaster over active damp.
Can you paint over damp walls?
No — it’s a cosmetic mask at best. Walls must be fully dry, the source treated, and sealed with a damp primer before applying moisture-resistant masonry paint. Without this, paint will peel within months.
What are the main causes of damp in UK homes?
Three causes account for almost all cases: rising damp (ground moisture travelling up masonry), penetrating damp (rainwater entering through defects), and condensation (warm air cooling on cold surfaces). Each requires a different fix.
Do I really need a damp specialist?
Yes — if damp keeps returning, mould is spreading, plaster is breaking down, or you’re buying or selling. A specialist diagnoses the root cause. Without correct diagnosis, no treatment will last.
Find the Right Guide
Every guide covers a specific problem — use these to find exactly what you need.
Damp Problems Explained
How to Treat Damp Walls
Damp Surveys & Diagnosis
Ventilation & Condensation
Damp Proofing Solutions
The Three Types of Damp
Almost every damp problem in a UK home falls into one of these three categories — and each requires a completely different fix.
Rising Damp
Ground moisture travels upward through masonry when the damp proof course fails or is absent. Typically affects walls up to 1.2m from floor level.
- Tide marks on lower walls
- Crumbling plaster at skirting level
- Salt deposits on brickwork
- Peeling wallpaper at the base
Penetrating Damp
Water enters horizontally through walls, roofs or floors due to structural defects. Can occur at any height — often misdiagnosed as rising damp.
- Damp patches appearing after rain
- Staining on ceilings or high walls
- Cracked or spalled external brickwork
- Faulty or overflowing gutters
Condensation
The most common issue in UK homes. Warm, moist air cools on cold surfaces — windows, external walls — and deposits water that leads to black mould.
- Black mould around windows and corners
- Streaming condensation on glass
- Musty smell in bedrooms and bathrooms
- Worsens in winter months
How to Fix Damp Properly
No matter the damp type, skipping any step means it will return.
Find the Source
Survey and moisture readings — not guesswork.
Fix the Cause
Treat the root problem, not just visible symptoms.
Remove Damage
Strip affected plaster, paint and wallpaper.
Apply Treatment
Correct product matched to the damp type.
Prevent Return
Improve ventilation and monitor moisture levels.
Damp Proofing Costs in London (2025–26)
Indicative costs for common treatments. Actual figures depend on severity, access and property type — always get a survey first.
| Treatment | Cost Range (inc. VAT) | Typical Average |
|---|---|---|
| Damp proof course (DPC) | £250 – £2,000 | £850 |
| DPC cream injection | £1,000 – £5,000 | £3,500 |
| External wall damp proofing | £750 – £2,500 | £1,500 |
| Cellar tanking (per m²) | £30 – £60 / m² | £45 / m² |
Prices are indicative and vary with severity, access and London postcode. Source data: MyBuilder Damp Proof Course Cost Guide.
The only way to get an accurate cost is a proper survey.
We assess, quote and explain everything before any work starts.
When to Call a Damp Specialist
These are the signs that mean DIY products won’t solve the problem.
Damp keeps returning after DIY fixes
Walls feel cold and wet year-round
Black mould is spreading quickly
Plaster is crumbling or breaking down
You’re buying or selling a property
Damp is affecting structural timbers
London’s Damp Specialists Since 2010
Damp & Mould Solutions Ltd works across London, from NW10 and beyond. We focus on accurate diagnosis first — never upselling unnecessary treatments. Company No. 12993370.
Not Sure What Damp You Have?
A survey is the only reliable way to diagnose the problem correctly — and it prevents costly mistakes. We cover all London boroughs.