i decided to redo the sealant round the inside of a double glazed window as it was a little drafty. there was a plastic strip at the top of the window which i removed. this has exposed a gap between the top of the window and the window opening in the wall, which is open to the cavity wall. i've checked a few sites about fitting windows and am guessing the window was too small when it was installed. i'm not sure if a gap like this should be filled with expanding foam or if i am best just putting it back the way it was, and having a look in the summer.
thanks
thanks