Why Plaster Keeps Falling Off Damp Walls in Ghana (2026)
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If plaster keeps blowing off the same wall, the plaster is not failing — it is being pushed off. Moisture travelling through the blockwork evaporates at the surface and leaves salt crystals behind, and those crystals expand with enough force to break the bond. Replastering without stopping the moisture just restarts the cycle.
What is actually happening
Water moving through a wall carries dissolved salts — from the blocks, the mortar, the sand, sometimes from the ground itself. When that water reaches the surface and evaporates, the salts stay behind and crystallise just under the plaster.
Crystal growth exerts real pressure. Over weeks it breaks the bond between plaster and blockwork. The plaster sounds hollow when tapped, bubbles, and eventually comes away in sheets, often bringing the paint and a layer of white powder with it.
That white powder is the clue. We cover it in detail in white powder on concrete walls. If you are seeing it, you are not looking at a plastering fault.
Where the water is coming from
| Source | How to recognise it | What fixes it |
|---|---|---|
| Rising damp | Worst at the base, stops at a fairly level line under a metre, present all year | Damp-proof course. Not a surface treatment. |
| Penetrating damp | Patches at any height, weather side, worse during rain | External water-repellent treatment or coating |
| Plumbing leak | Localised, often near a pipe run or bathroom, does not care about weather | Find and repair the pipe |
| Leak from above | Starts high, runs down, worse after rain | Roof, parapet or gutter waterproofing |
| Ground splashback | Lower 300-400 mm only, worst where rain hits hard standing | Drainage, plus surface treatment |
Getting this right matters more than the repair itself. The single most expensive mistake is treating penetrating damp as rising damp, or the reverse — see rising damp vs penetrating damp.
Why replastering alone always fails
New plaster goes onto a wall that is still carrying moisture and salts. The moisture keeps arriving. The salts are still in the blockwork. Within a season or two the same crystals form behind the same plaster and push it off again.
We have seen walls replastered four times in three years. The plasterer is not at fault, and nor is the material. Nobody dealt with the water.
The order of work that actually holds
- Identify the source. Use the table above. If it is a leak, fix the leak — everything else is pointless until you do.
- Strip back to sound blockwork. Remove all loose and hollow plaster, plus 300 mm beyond the visible damage in every direction. Salts spread further than the staining shows.
- Let it dry. This is where most people lose patience. A block wall needs weeks, not days. The dry season is the right time to do this work in Ghana for exactly this reason.
- Stabilise the surface. Once dry, blockwork and old mortar are often chalky and weak. A sand fixing agent penetrates 5-10 mm and consolidates it, giving the new plaster a solid base and reducing how much water the face takes in.
- Treat the source properly. Penetrating damp through a porous external wall needs the external face treated. Rising damp needs a damp-proof course — there is no shortcut.
- Replaster last. Only when the wall is dry and the water is dealt with.
The honest limit
We sell a product that helps at step four, and we are not going to pretend it does more than that. Consolidating and water-repelling a wall face stops rain soaking in from outside. It does nothing about groundwater rising from below.
If your wall is wet at the base, dry a metre up, and stays that way through the dry season, no liquid applied to the face will fix it. Anyone who tells you otherwise is selling you a product that will fail and take your new plaster with it.
Doing it in the right season
November to March is the window. You need the wall to dry out, and with Accra taking around 800 mm of rain a year and Kumasi nearer 1,400 mm, a wall you strip in June will not dry before you have to close it up. Harmattan does the drying for you.
Send us a photo of the wall and we will tell you which problem you have. Call 0555 548 001 or 0241 737 026, or book a free site assessment in Greater Accra.
Related Resources
- Rising Damp vs Penetrating Damp in Ghana
- White Powder on Concrete Walls (Efflorescence)
- How to Stop Damp Walls Permanently in Ghana
- Peeling Paint on Exterior Walls — The Permanent Fix
- Sand Fixing Agent in Ghana — Complete Guide
Fest Ghana Limited is the trading name of FGL Waterproofing Solution Limited Company, a company registered in Ghana — Registration No. CS218171026. Company information.