- Penetrating damp is rainwater getting through the outside of a building and showing on the inside.
- In Cape Town it usually appears in winter, when rain is driven against exposed walls.
- The fix is finding and repairing the entry point, not just treating the stain inside.
- Describe the problem once and compare quotes from contractors across Cape Town.
Tell us about the problem and compare quotes from penetrating damp treatment specialists in Cape Town.
Compare QuotesSigns of Penetrating Damp
- Damp patches that appear or spread after rain and fade in dry weather.
- Stains at any height, often around windows, below parapets or at roof junctions.
- Blistering paint or efflorescence on exposed outside walls.
- Mould on the inside face of a cold, exposed wall.
Common Entry Points and What to Check
- Cracks in plaster and render. Hairline cracks let wind-driven rain in.
- Window and door seals. Failed sealant around frames and sills.
- Parapet walls and copings. Common on flat-roofed Cape Town homes.
- Roof-to-wall junctions and flashings. Lifted or missing flashings.
- Gutters and downpipes. Overflowing or leaking onto the wall.
- Cavity walls. Mortar on wall ties or blocked weep holes can carry water across.
An assessment should link the inside stain to a specific outside defect, check whether the damp changes with rain, and rule out plumbing leaks.
Repair Options and Their Limits
| Option | When it is used | Limitations |
|---|---|---|
| Crack repair and replastering | Cracked render letting water in | Cracks can return if movement is ongoing |
| Resealing windows and doors | Leaks around frames and sills | Needs regular checking in coastal areas |
| Parapet and coping waterproofing | Water entering from the top of walls | Must tie in with the roof waterproofing |
| Flashing repairs | Leaks at roof-to-wall junctions | Can involve roofing work and access equipment |
| Exterior waterproof coating | Porous or exposed walls | Does not fix structural cracks or failed details |
What the Work May Include
- Inspecting the outside face, roof edges, gutters and openings.
- Opening and repairing cracks, then patch plastering.
- Resealing frames, waterproofing parapets and fixing flashings.
- Applying an exterior waterproof coating or elastomeric paint where needed.
- Repairing inside plaster and paint once the wall has dried.
Penetrating Damp Treatment Prices in Cape Town
| Item | Ballpark price |
|---|---|
| Fixing the defect and sealing the wall, per m² | R120 - R250 |
| Exterior wall waterproof coating, per m² | R80 - R150 |
| Parapet walls and copings, per metre | R220 - R400 |
| Roof-to-wall junctions, per metre | R250 - R450 |
| Window resealing, per window | R400 - R900 |
Ballpark figures, not quotations. Indicative 2026 ranges, rounded, from published South African damp-proofing, waterproofing and plastering price guides (Cape Town and Western Cape guides where available, national and Gauteng guides otherwise), checked October 2026. Per-metre prices are per linear metre of wall unless stated. Some include VAT and some do not, so confirm VAT on every quote. A site assessment and a written quote set the actual price.
What changes the price
- Height and access: ladders, scaffolding or a cherry picker.
- How many defects there are and how spread out.
- Coating system and number of coats.
- Whether interior plaster and paint repairs are included.
Getting Penetrating Damp Quotes
Say where the damp shows, which way the wall faces and whether it follows rain. Photos of the inside and outside help. Compare quotes through Damp Proofing Cape Town.
Frequently Asked Questions
How do I know if it is penetrating or rising damp?
Penetrating damp usually follows rain and can appear at any height. Rising damp stays low on the wall and is more constant. An inspection confirms it.
Will waterproof paint fix it?
Only if the wall itself is porous. Cracks, failed seals and flashings have to be repaired first.
Why is my damp worse in winter?
Cape Town's rain falls mostly in winter and is often wind-driven, so exposed walls get wet more often.
When should repairs be done?
Outside repairs and coatings need dry weather, so many people book them for spring and summer.
Is this covered by home insurance?
It depends on your policy. Gradual damp is often excluded. Check with your insurer.
Related Pages
Damp Proofing Cape Town is a free quote-comparison service. Damp is inspected, quoted and repaired by independent damp proofing contractors, and your agreement is with the contractor you appoint. Ask each one for a written, itemised quote, what is and is not included, guarantee terms and payment terms before paying anything.
Penetrating Damp Treatment Cape Town. Describe the damp once and compare penetrating damp treatment quotes.
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