1. Clear the drainage slots
Do this one even if you do nothing else.
Look along the bottom of the frame, outside, for small slots or holes — usually two or three per opening, sometimes behind a small plastic cover. On a sliding window, look along the bottom track.
They exist because the window is designed to let some water into the bottom rebate and drain it back outside. Mumbai dust silts them up, and then the water has nowhere to go.
Clear them with a thin brush or a folded cloth, then test: pour a little water into the track or rebate and watch it come out the other side. If it pools, they are still blocked.
Never seal these. It is the most common well-intentioned mistake, and it turns a drained frame into a reservoir.
2. Press the gaskets
The rubber or EPDM strip the sash closes against. Press it firmly with a thumb and let go.
- Springs back — fine.
- Stays compressed, feels hard, or has cracks at the closing edge — it has lost its elasticity and is no longer sealing.
Hardened gaskets are why a window that looks shut lets in road noise, dust and driven rain. They are cheap, they are consumables, and replacing them is the highest-value small job on a window. Padding them out with foam tape is not a fix — it closes the gap and jams the sash.
3. Check the perimeter seal
The line of sealant outside, between the frame and the wall.
Look for shrinkage, cracks, and lifting — the corners go first, and a failed corner is usually where water starts tracking down inside the reveal.
If you find one, do not smear new sealant over the old. The old material has to come out and the surface has to be clean and dry, or the repair fails in a season. That is a job for window sealing.
4. Work every sash
Open and close each one fully. Throw every lock.
You are checking for:
- Stiffness or catching — usually a dropped hinge, grit in a slider’s track, or a timber sash that has swollen
- A handle that turns without locking — the multi-point gearbox has failed, and since those locking points are what pull the sash onto its gasket, the window has stopped sealing as well as stopped locking
- Rattling when pushed — the sash is not being drawn tight
A sash you have to shove to close is not compressing its seal. That is an adjustment now and a replacement part later.
5. Look at the glass and the beads
Fogging between the panes means the sealed unit has failed and moisture is in the cavity. It cannot be dried out; the unit gets replaced — see glass replacement. The frame is usually fine.
Loose or lifting glazing beads let water reach the edge of the unit, which is what causes that failure in the first place.
Then the roof-level things
If you have a skylight or a terrace door, add two more:
- Clear leaves and debris off the skylight and out of its surrounding gutter. An upward-facing opening collects everything.
- Check the threshold drainage on the terrace door. It is the same weep-hole principle at floor level, and it is where balcony-door leaks come from.
What this prevents
Not inconvenience — cost. Water sitting in a frame is what rots timber, corrodes steel from the fixings outward, and softens the plaster behind a reveal. Every one of those starts as a blocked slot or a tired gasket, and every one of them is cheap this month and expensive in August.
If something on the list needs more than a cloth, window maintenance covers the annual version of this done properly, and window frame repair covers what happens when it has been left too long.