Exterior Wall Waterproofing in Ghana — Complete Guide (2026)
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Exterior Wall Waterproofing in Ghana
Unpainted or poorly finished blockwork absorbs driving rain directly. The fix is a breathable, elastomeric coating applied to the external face — not a sealed film, and not internal treatment. Expect GHS 60–110 per m² for a complete system.
Why Ghanaian External Walls Let Water Through
- Porous sandcrete blocks. Standard Ghanaian blocks absorb water readily. Unpainted, they act like a sponge in heavy rain.
- Driving rain. Storm intensity up to 100 mm/hour, wind-driven horizontally against one elevation — usually the south-west face.
- Hairline cracking. Thermal movement of 20°C daily opens fine cracks in render that are invisible dry and open in rain.
- Failed or thin render. Hollow-sounding areas where render has debonded hold water against the block.
- Coastal salt. Within 15 km of the ocean, salt crystallisation inside the block breaks up render from within.
The System
| Stage | What happens |
|---|---|
| 1. Survey | Identify cracks, hollow render, ground levels, splash zones |
| 2. Clean | Remove algae, dust, chalking paint, loose material |
| 3. Repair | Rout and fill cracks; replace hollow render |
| 4. Prime | Stabilise porous substrate; chloride-blocking primer if coastal |
| 5. Coat | Two coats elastomeric, breathable, perpendicular application |
| 6. Details | Window and door perimeters, pipe penetrations, copings |
The Breathability Rule
This is the part people get wrong.
An external wall coating must stop liquid water getting in while still letting water vapour out. Walls always contain some moisture — from construction, from humidity, from below. If it cannot escape outward, it accumulates.
Seal a wall with a non-breathable film and you get blistering, render debonding, and internal damp that appears months later and looks unrelated.
Ask any supplier one question: is this coating water-vapour permeable? If they cannot answer, do not buy it.
Fix These First — They Cause More Damp Than Porous Walls
- Ground level above the damp-proof course. Soil or paving piled against the wall bridges the DPC entirely. Lower it.
- Splash-back. Rain bouncing off hard paving soaks the bottom 300 mm of wall. A gravel margin fixes it.
- Blocked or broken downpipes. A single failed downpipe discharging onto a wall does more damage than years of driving rain.
- Missing or short copings. Parapet and boundary wall tops must shed water clear of the face.
- Air-conditioning condensate. Constantly wetting one patch of wall.
Coating over any of these wastes money. The water keeps arriving.
Costs
| Scope | Cost |
|---|---|
| Full external wall system | GHS 60–110 / m² |
| Coastal (within 15 km) | +15–20% |
| Crack repair only | GHS 180–320 / lin m |
| Render replacement | GHS 90–150 / m² |
| Access above 2 storeys | Scaffolding priced separately |
When to Do It
December to March. The wall is genuinely dry, there is no rain risk during cure, and the system is settled before the April rains test it. Applying external waterproofing during the rainy season rarely works — the substrate is never dry enough.
Book an Assessment
Free survey identifying whether your damp is driving rain, rising damp, a roof defect above, or plumbing — before we quote anything.
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