How to fill a 15mm gap between upvc window frame and brick?

[dispam]

Hi..I suspect my windows were originally wrongly sized and now the stuff (whatever it is) that was used to fill the gap between frame and wall is now crumbling and falling out. I realise I can't just fill the gap with some kind of sealant, it's too wide. But how would I fit a piece of upvc into the gap? And then what? I would be really grateful if someone could help. Even if I couldn't do it myself I would like to know the best way of doing it so I can spot any other potential cowboys and further botch up jobs. Thanks so much.

[JRS]

Its not the wrong size window just the fitter has packed them out too much. you will need silicone sealant or decorators caulk (recommended) due to being waterbased. fill the gap then wash with a cloth to smooth and clean excess.

[brithebuilder]

Hi, you could use expanding foem to fill the gap then fix a UPVC trim over it. Just be carefull you don't overfill the gap because the foam will distort the frame if it hasn't been packed off the double glazed unit all around.