Expanding Foam Question

Tidyweb

I wan to fill a gap under a window sill.

Its between the walls and so I have no idea how big the gap it. Its probably about the of a litre bottle.

Anyway, if you pump in too much expanding foam can it cause damage, will it work considering it wont have room to expand - or will it just expand out the hole I put it in one the hole is full.

There is a window above the hole so I dont want to damage the window.

Thanks

bette

That stuff is soft and it's easy to cut with a sharp knife or a Stanley blade. Just don't go mad with the stuff. Try a small bit first and you'll see that it goes up to 10 times it's original size!

Tidyweb

But I have no real idea of the size of the hole, so knowing how much it expand is worthless really.

And the hole I am using to insert the foam is the size of the application nossle, I cant make it bigger because of the window above it.

Tom Joad

Tidyweb wrote: »

But I have no real idea of the size of the hole, so knowing how much it expand is worthless really.

And the hole I am using to insert the foam is the size of the application nossle, I cant make it bigger because of the window above it.

Are you filling under the window sill for insulation purposes?

If so, I can say from trying to do it this way that its not really much of a success. Ended up taking off the windowsill and filling underneath with expanding foam. - put the windowsill back on straight away and weighed it down - extra foam just wept out where there was a gap and was easy to cut. Really worked in keep the heat in the room.

Tidyweb

Damp Proof / weather proof wasnt installed correctly and water getting in between corner of window and the sill.

Will seal it up with Sealant, but want to double up by filling void under window.

whizbang

you can pump in till the cows come home..it wont cause any damage.

if it starts coming out the chimney, you better stop.

However this stuff is not waterproof. it will suck moisture, eventually loosing insulation properties.