Expert Guides
Practical, jargon-free guides on identifying, treating and preventing damp — written by London specialists with over 15 years in the field.
Quick Answers
Common Damp Questions
Straight answers to the questions we hear most — no filler.
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.
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.
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.
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.
Resource Library
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
Understanding Damp
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
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
The Right Approach
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.
Skip step 1 or 2 and the damp will come back — regardless of how well steps 3–5 are done. This is why DIY products often fail long-term.
Pricing Guide
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.
Don’t Wait
When to Call a Damp Specialist
These are the signs that mean DIY products won’t solve the problem.
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.
Ready to Resolve It?
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.