A damp wall has a cause. Find it before you treat it.

Reading the wall

Where the stain sits says almost everything. Low, even, along the length: rising damp. In a corner, up high, behind furniture: condensation. Under a window, around a sill, under a terrace: water coming in. Always the same spot, whatever the weather: a leak. On a wall whose other face touches soil: lateral damp.

The second clue is the calendar. A stain that grows after rain comes from outside. A stain that grows in winter, when windows stay shut, comes from the air in the house.

Why diagnosis comes first

On Belgian forums the stories of failed treatments all sound alike: an injection sold in one visit, on a wall that was actually suffering from a cracked gutter or a badly sealed terrace. The wall stayed damp, and the owner paid twice.

So we measure at several heights, look outside as much as inside, and write down what we found before pricing anything. If the cause is not our trade, a roofer, a plumber, we tell you.

What we do

Cut the cause: injection for rising damp, repointing, sill or waterproofing repair for water coming in, ventilation and cold-spot insulation for condensation, digging out and sealing for a wall against soil.

Restore the wall: strip the damaged plaster, desalt, renovation render or plastering, vapour-permeable paint. Renovation and painting are done by the same group.

Check: a reading a few weeks later, to be sure the wall is drying as planned.

What it costs

It depends on the cause. Repointing is priced per m², injection per metre of wall, ventilation per room. The visit for a quote is free in Brussels and Brabant wallon, and market ranges are on our prices page.