Why is my window leaking or rattling?

Window leaking in the rain or rattling: the usual causes

A window usually leaks or rattles because the seals, sealant, tracks or fittings that keep it watertight and steady have worn out or worked loose. You can check and clean it yourself, using the steps the Building and Construction Authority (BCA) gives homeowners. If the window itself needs replacing in an HDB flat, HDB says the work must be done by a BCA Approved Window Contractor listed in its directory.

Rain usually finds its way in at a few points. Rubber seals shrink, harden or crack with age and leave gaps. Sealant around the frame can fail and let water in between the frame and the wall. On sliding windows, dirt can block the drainage in the tracks, so water collects and spills inside instead of draining away. If you have a window leaking in the rain, note where the water appears first: at the seal, around the frame or along the track.

Window rattling usually comes from worn seals, loose handles or worn rollers on sliding panels. Once a seal has shrunk or a part has worked loose, the panel can shift in its frame when the wind blows.

BCA notes that windows deteriorate with wear and tear from wind and rain. A leak or rattle is a good reason to check the whole window, not just the part you noticed.

Window rubber seal checks you can do

BCA gives homeowners three steps: check, clean and change. HDB asks you to check your windows once every 6 months to make sure they work smoothly and have no loose or worn-out parts, because windows that deteriorate can fall and cause serious injury to passers-by.

Practical checks you can do yourself:

• Look along the rubber seal for gaps, cracks or hardening.
• Clear dirt and debris from the tracks of sliding windows.
• Check handles, rivets and stays for looseness.
• During rain, note where the water comes in.

If you are not confident checking your own windows, BCA suggests engaging an approved window contractor to inspect them, and HDB owners refer to HDB's list. You can read more about a window safety inspection before you book one.

Who should fix it in an HDB flat

HDB's window works guidelines say all window installation or replacement work must be done by a BCA Approved Window Contractor listed in HDB's directory. A renovation permit from HDB is required for all window replacement work, and the contractor applies for it. As the flat owner or occupant, you are responsible for the upkeep of the windows in your flat.

HDB also says owners face penalties if a window falls through lack of maintenance. A window that shifts, sags or sits out of line in its frame needs urgent attention, not a wait until the next routine check.

Before you book, ask the contractor whether your job counts as window works. A worn seal, a loose handle and a whole new window may be handled differently, and the answer tells you whether a permit is involved. When you compare companies for door and window repair, ask each one whether it is an approved window contractor before it works on a window.

Casement window rivets and grilles

BCA says approved window contractors retrofit casement windows by replacing all aluminium rivets at the window stays with type 304 stainless steel rivets. HDB says owners who fail to retrofit casement windows with stainless steel rivets face penalties. If your flat has casement windows, ask an approved window contractor to check the rivets.

If you are considering grilles, HDB's window works guidelines say internal metal grilles of any design at windows and the balcony parapet need no permit. For flats handed over before mid-2007, grilles must be fixed internally and cannot protrude from the building facade. For flats handed over from mid-2007 onwards, grilles at the service yard or balcony parapet need a permit and must be of HDB-approved designs, shown in the renovation factsheet or on MyHDBPage.

To weigh up the options, see invisible or traditional grilles. For other questions about windows and doors, read the windows and doors FAQ.

When water reaches the wall

Water that runs down inside the wall below a window can stain the paint and feed mould. Fix the window first, then repair the wall, so you are not repainting a wall that is still getting wet. For the wall itself, read about water seepage in a wall and painting over mould.

HDB reminds owners that engaging a window contractor is a private arrangement. Before any repair, note the type and extent of work and all chargeable costs. Compare quotes from more than one contractor and study the terms before you agree.

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