Diagnosis before treatment
The mistake we're most often called in to undo is treating the stain instead of the cause. Sealed and repainted, it looks solved for a season and comes back worse.
- Establish whether it's ingress, plumbing, rising damp or condensation
- Trace the actual entry point — often nowhere near the visible patch
- Check roof, terrace, balcony and parapet detailing for failures
- Rule out slow plumbing leaks behind walls and under floors
- Photograph everything, so you can see the reasoning, not just the bill