The pattern is so common it is almost a season of its own. A patch appears above the bathroom door or behind the wardrobe. Somebody scrapes it, puts a coat of paint over it, and it looks fine. Then the monsoon arrives and it is back, slightly bigger.
This is not bad paint. It is the wrong repair.
A damp patch is a symptom, not a fault
Water is arriving from somewhere. Paint is a coating on the room side of the wall, which is the far end of the journey — sealing it there is like closing the last door in a corridor and hoping the water goes home. It does not. It spreads sideways inside the plaster and comes out somewhere else, which is why a patch that gets painted over tends to reappear larger and often a little to one side.
The usual sources, in the order we find them
- The terrace above. The commonest one in Noida's high-rise stock. Ponding water finds a crack in the coating and travels along the slab.
- A plumbing joint. A slow drip inside a chase, often at a bathroom or kitchen wall. This one is usually the same size all year and does not care about the monsoon — a useful tell.
- The external wall. Driving rain on a wall whose exterior coat has failed, or an unsealed junction around a window frame.
- Rising damp from the floor slab. Rarer in apartments, common in ground-floor and independent houses.
- A neighbour's bathroom. Unwelcome news, but it happens, and it is worth knowing before you spend anything.
What a real job looks like
The sequence matters more than the material:
- Measure the moisture at the patch and around it. This is how you find the edge of the wet area, which is almost always bigger than the stain.
- Find the source. Sometimes obvious, sometimes it needs the terrace flooded and watched for an hour.
- Treat the source. Terrace coating, a plumbing repair, an external wall treatment, a resealed window junction — whichever it turns out to be.
- Open up the affected plaster where it has blown. Painting over blown plaster fails no matter what is behind it.
- Let it dry. The step everybody skips. A wall that has been wet for months does not dry in two days, and sealing moisture in guarantees a repeat.
- Replaster, prime and repaint. Only now.
Do it before the rain, not during
Waterproofing wants a dry surface and a dry forecast. Terrace coatings need to cure. Once the monsoon is running you can stop the bleeding, but the durable repair is a pre-monsoon job — which is why April to June is when this work should be booked, and August is when everyone actually calls.
When we will tell you not to bother
Some seepage is structural or comes from the common area, and treating your side of it is money spent on a symptom. If that is what we find, we will say so on the report rather than sell you a coating that will not hold. It is a worse day for us and a much better one for you.
The survey is free either way.