Perished rubber gaskets are a common, often overlooked cause of draughts, noise and even damp around windows.
Every uPVC or aluminium window has rubber gaskets running around the sash and frame that compress when the window closes, creating an airtight and weathertight seal. These are separate from the sealed unit itself (the glass) and are a wearable, replaceable component rather than a permanent fixture — they are designed to be swapped out periodically over the life of the window.
Look for rubber that has gone hard, brittle, or visibly cracked, sections that have shrunk and pulled away from the corner joints, or a gasket that no longer springs back when pressed. A window with failed gaskets often feels draughty even when properly closed and locked, and can let in a whistling noise in windy conditions.
It's easy to confuse a perished gasket with a failed sealed glass unit, but they are different problems: gasket failure causes draughts and noise around the edge of the sash, while sealed unit failure causes misting between the panes of glass. Both can occur on the same ageing window, but only one requires new glass.
Gaskets are sold by profile and can usually be sourced to match the specific window manufacturer, then pressed into the existing channel around the sash — a straightforward job for an experienced fitter and one of the more cost-effective window repairs available, often resolving draughts and whistling completely.
Good quality EPDM rubber gaskets typically perform well for well over a decade, but UV exposure, extreme temperature cycling, and simply the age of the window all accelerate wear. If your windows are approaching or past 15-20 years old, checking gasket condition is a sensible part of a general window health check.
A draught around the edge of a closed sash points to the gasket, while misting between the panes points to a failed sealed unit. The two problems have different fixes, so it's worth identifying which applies before booking a repair.
Yes, gaskets are a standard replaceable part and can usually be swapped for the correct matching profile, restoring the seal without touching the glass or frame.
Well-made rubber gaskets often last well over a decade, though sun exposure and temperature extremes can shorten this. It's worth checking gasket condition on windows approaching 15-20 years old.
In most cases yes, since whistling is typically caused by air passing through a gap left by a shrunk or perished gasket rather than a fault with the glass or frame.
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Book a free survey and we'll check whether it's your gaskets, your glass, or time for new windows.
