What it looks like
- Paint bubbling or peeling, plaster crumbling.
- White salty powder on the brick or plaster.
- Dark wet patches, a musty smell, or mould spots.
Where the water comes from
- A leaking pipe inside or behind the wall, or a leaking bathroom or kitchen above.
- Rain getting in through the roof edge, a cracked outer wall, a window frame or a blocked rainwater pipe.
- Water from the ground rising up into the lower part of the wall, which is common where the ground outside is higher or drainage is poor.
- Condensation in a closed, poorly ventilated room.
What to do
- Notice where and when it gets worse: after rain, after using the bathroom, or all year. This tells the mistri a great deal.
- Fix the source first (pipe, roof edge, crack, drainage). Then let the wall dry fully, which can take time.
- Only then scrape the damaged plaster, re-plaster and paint. Painting over a wet wall hides the problem for a short time and it returns.
- If a pipe may be leaking inside the wall, ask a plumber to check before anyone breaks the wall open.
- If the wall is a load-bearing wall and the cracks are wide or growing, ask a qualified person to look at it before repairs.