Mumbai gets most of its year's rain in four months, and flats in Mira-Bhayandar, close to the creek and the sea, take it from the side as well as from above. Every October and November we see the same problems: damp patches, peeling paint, swollen wardrobe doors and tiles lifting near balconies. The good news is that most of them can be prevented with work done in the dry months. Here is what to check and fix, in the right order.
1. Find where the water is coming from
A damp patch inside is a symptom, not the cause. Water usually enters from one of five places: cracks in the external wall plaster, gaps around window frames, a leaking bathroom above or beside the wall, a terrace or chajja above, or a concealed pipe. Painting over the patch without fixing the source only hides it until the next monsoon. Before any repair, we trace the source by checking the wall from outside, the bathroom on the other side, and the window joints.
2. Seal windows and frames
Many leaks come from old aluminium sliding windows. The bottom track fills with rain and overflows into the room, or the silicone between frame and wall has cracked. Cleaning the weep holes, resealing the frame with good silicone and adding a slight slope to the outer sill solves most of these. For badly worn windows, UPVC windows with proper drainage are a long-term fix.
3. Treat external cracks
Hairline cracks in external plaster let water soak into the wall. In a society building, external repairs are usually the society's responsibility, so raise it with the committee early in the dry season. For bungalows in Uttan, Gorai and Vasai, we fill cracks, apply a waterproof coating and repaint with exterior emulsion.
4. Bathrooms and balconies
Failed bathroom waterproofing does not only affect the flat below; it can soak the walls of your own bedroom next to it. Signs include damp skirting near the bathroom door and peeling paint on the shared wall. Regrouting joints with epoxy can stop small leaks. If the waterproofing layer has failed, the bathroom needs breaking and redoing. Balconies need a slope towards the drain and a waterproofed floor, especially if they have been enclosed.
5. Protect wardrobes and kitchens
Wardrobes built against external walls or bathroom walls absorb moisture. Doors swell, laminate peels and clothes smell musty. When building new furniture, ask for BWR or BWP plywood, a small air gap or a laminate backing against the wall, and a raised base on legs or a plinth. In kitchens, BWP plywood under the sink is a must.
6. Then fix the inside finish
Only after the source is fixed and the wall has dried should you re-plaster and repaint. Damp plaster is cut out, the wall is allowed to dry, and a waterproof putty or primer is used before emulsion. Doing this in October to May gives the wall time to dry properly.
Electrical safety in the monsoon
Water near wiring is dangerous. If switches near a damp wall spark or the MCB trips in the rain, get the wiring checked. An RCCB (residual current circuit breaker) on the main board protects against shocks and is a small cost during any rewiring.
Best time to do the work
The ideal window is October to April. Plaster cures properly, paint dries, and waterproofing can be tested before the next rains. Work done in June and July often fails because walls never dry.
What it typically costs
Small fixes are inexpensive: resealing a window frame or regrouting a bathroom with epoxy usually costs a few thousand rupees. Redoing bathroom waterproofing properly, with breaking, a new waterproof layer, ponding test and fresh tiles, is a bigger job and usually part of a bathroom renovation. Cutting out damp plaster and repainting a wall falls in between. Because the cause decides the cost, we always inspect before quoting, and we tell you if a cheaper fix is likely to be enough.
Quick pre-monsoon checklist
- Clean window tracks and weep holes; reseal frames.
- Check the bathroom-shared walls for damp skirting.
- Clear balcony and terrace drains.
- Report external cracks to your society.
- Check that wardrobes against external walls are not touching damp surfaces.
- Test the RCCB on your main board.
If you see damp patches in your flat in Mira Road, Bhayandar, Dahisar or Borivali, WhatsApp us a few photos. We will tell you what is likely causing it and whether it needs a visit.