Gaps to sides of upvc windows

5 Dec 2012
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United Kingdom
We are in the process of redecorating our house and have found some very large gaps to the sides of all the upvc windows. They have been covered up by upvc window trims (if that's what they're called). The window trim is also on the outside of the house as well as inside. I can actually see outside when I look though the gaps, so these trims aren't doing a lot of good.

I am worried about draught and water getting through and wondered what is the best way to seal this.

Pic below.

Thank you in advance
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Expanding foam is the only way now, leave the trims on on one of the sides in or out and then foam the void, don't go mad with the foam though.

If you have a lot to do i would suggest you invest in a foam gun, much easier to use as you have more control, buying the standard aerosol based foam cans means once you've started a can you need to finish it as the foam will harden in the nozzle rendering it useless, heres an example of what you need....

You will find all you need at screwfix or even a local eurocell branch
Thanks for your quick reply. A few questions:

Do I use the expanding foam from the inside or outside? Does it matter?

I was thinking of taking off the trims from the outside too and sealing this again also. Do I need to put the trims back on?

What do I use after the expanding foam on the outside?

Thanks again

Inside outside doesn't matter.

Yes take trims off from outside and squirt foam in the gap, once cured after about half hour trim off the xs and refit the trim unless you think it is a sealable gap so then just use silicone sealer
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Great, thanks for your help. I just have to wait for the temperature to rise so I can use the foam!
Spray water onto the frame and anything else where you dont want to be cleaning excess foam off.....Once you have filled any gaps,spray foam with water again,as this will stop it expanding so much and will make it safe to touch without getting it all over your its a nightmare to clean off.

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