Damp at the Base of a Wall — Apam, Gomoa Case Study 2026

A house at Apam in Gomoa, a few hundred metres from the sea, with render blowing off the bottom of the external wall and staining inside at skirting level. It had been patched before. This is what we found, why the earlier repairs failed, and the order of work we used to put it back.

Watch the repair

Chapters: 00:00 The problem · 01:46 Strip back to sound blockwork · 02:31 Mixing the slurry · 03:11 Rendering back on

What the owner saw

Two things, and most people only report the first.

Outside: render blown off the base of the wall in a band, exposing blockwork, with more sounding hollow around the edges of the damage. Decorative stone cladding below the damaged band was still sound.

Inside: a dark line along the bottom of the wall where it meets the tiled floor. This is the detail that matters. Damp showing on both faces of the same wall, at the same height, points at the wall itself rather than at weather hitting one side.

What we found

A tap test across the elevation marked out far more hollow render than the visible damage suggested — the failure extended well past where the material had actually fallen away. That is normal and it is why patching to the edge of the hole never holds.

The pattern was a band along the base with a reasonably level top edge. That shape is characteristic of moisture rising through the blockwork rather than rain driving in, which would give scattered patches at varying heights. We set out the difference in rising damp versus penetrating damp.

Apam sits on the coast, and that matters. Salt-laden ground and salt-laden air both load the blockwork with chlorides. Salt crystallisation is what physically pushes render off a wall, and coastal walls carry more of it than inland ones. The same defect in Koforidua would usually be less aggressive.

Why the earlier patching failed

Somebody had already made this good at least once. The work was not bad — it simply ignored three things:

• It was cut back only to the visible damage. Salt-loaded blockwork was left right at the joint, and the new render failed along that line.
• The wall was still wet when it was closed up. A block wall takes weeks to dry, not days — see how long a damp wall must dry.
• Nothing was done about the water. Re-rendering is a repair to the symptom. It restarts the clock and nothing more.

The work

1. Map it. Tap test across the whole elevation, marking every hollow area, then set the cut line 300 mm beyond the furthest hollow point.
2. Strip back to sound blockwork. Hammer and chisel, down to clean block and raked-out mortar joints. All debris cleared — dust left on the face is what the next failure bonds to.
3. Let it dry. The unglamorous step, and the one that decides whether the repair lasts. Exposed blockwork dries far faster than blockwork sealed behind render.
4. Prepare the surface. Blockwork that has been wet and dried repeatedly is chalky at the face. It needs consolidating so the new render keys into solid material rather than powder.
5. Apply the waterproof slurry. Mixed on site and worked into the blockwork and joints, not just skimmed across.
6. Re-render in layers, built back out to the original line and finished to meet the existing render and the stone cladding below.

The honest part

Where moisture is rising from the ground, surface work manages the symptom well and does not remove the cause. A proper damp-proof course is the only thing that stops groundwater climbing a wall, and that is a different and larger job than re-rendering.

We say so on site rather than afterwards. A customer who understands that a base-of-wall repair on a coastal house may need revisiting is a customer who is not surprised in three years. A customer who was promised a permanent cure is a complaint waiting to happen.

What to take from this if your wall looks similar

What you see	What it suggests
Band at the base, level top edge, both faces	Moisture rising through the wall
Patches at varying heights, one elevation	Rain driving into a porous wall
Vertical strip near a bathroom or kitchen	Plumbing leak in a chase
Repaired before, failed in the same place	Cause never addressed, or cut back too tight

Run the tap test before anyone quotes you. Twenty minutes with your knuckle tells you how big the job actually is, and stops you paying for a patch that fails.

Coastal walls need more

Within about 15 km of the sea — Apam, Winneba, Nungua, Teshie, Sakumono, Tema — salt makes every damp problem more aggressive and every repair shorter-lived. Budget for better preparation and expect to inspect more often than you would inland. Our notes on coastal salt protection go into the detail.

Damp at the base of your wall? Send photos of the inside and the outside at the same point. Call 0555 548 001 or 0241 737 026, or book a free assessment.

Related Resources

• Why Plaster Keeps Falling Off Damp Walls
• Hollow-Sounding Plaster — The Tap Test Guide
• How Long Must a Damp Wall Dry?
• Rising Damp vs Penetrating Damp in Ghana
• Coastal Salt Protection for Sea-Facing Homes

Fest Ghana Limited is the trading name of FGL Waterproofing Solution Limited Company, a company registered in Ghana — Registration No. CS218171026. Company information.