I need to try to prevent drafts coming through and around my double glazed window units as much as possible. How can I go about detecting and sealing any leaks that are letting air through the window? Preferably without having to remove the windows.

I would like the solution to be a permanent as possible.

(I have arranged alternative source/extract of ventilation air so there are no problems with reducing the leakage of the windows)

  • 1
    Could you be more specific about where the air is coming from? Around frame of jambs? windows loose in jambs? Outside of pre-hung frame? Commented Mar 4, 2011 at 17:24
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    Exact dup? diy.stackexchange.com/questions/1029/prevent-window-drafts Commented Mar 4, 2011 at 17:36
  • The windows are, for some reason, an aluminium frame inside a wooden frame. It seems to me most likely that air is getting through either where the aluminium meets the wood frame, or where the wood frame meets the wall. Especially on the outside the fit doesn't seem to good. I don't think the actual windows inside the aluminium frame are leaking, although any suggestions on how to check would be appreciated. Commented Mar 6, 2011 at 14:21

2 Answers 2


Start by removing the trim from around the window, this will give you a good look at the problem. Once you have the trim removed you'll be looking at something similar to this...

enter image description here

You may notice gaps between the window frame and the wood frame or between the wood frame and the wall, these are the areas you'll want to fill to stop the draft.

Get a can spray foam (like GreatStuff they make some specifically for this purpose, which is "low pressure" so it will not bow the window frame), fill any gaps (be careful not to use too much, this stuff can expand quite a bit). Once the foam has hardened (about an hour), use a sharp knife to trim the excess foam so it's flush with the window frame. Reinstall the window trim, and your done.


My comment was wrong. My windows are Aluminum, and most of the air leakage was being caused by the degraded state of the Brush Pile Weatherstrip which is supposed to seal around the edges of the opening part of the window.

Brush Pile Weatherstrip is a kind of furry strip of plastic that sits in a groove around the edge of the window. You can buy replacement strips, then prise the old stuff out, cut the new stuff to length and force it back into the slots.

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