Window Seal Advice

[bottler]

Looking for advice on sealing around newly installed windows.

I'd like them to be Air-Tight and Sound-Proof as on a main country town road.

The gap is quite large, as old Sash Windows with weights have been removed. Pics below...

I've been told to avoid Expanding Foam - as it can bow windows? And mine are UPVC Sash Windows, so they need to be able to slide up & down.

If I was to pack them with Rock wool / Fiberglass Insulation I'm guessing the Sound Proofing wouldn't be great?

I've also been told to try Low Expansion Foam as it doesn't expand as much (2:1 ratio) - plus it has a higher density, better soundproofing. But I'm scared to do so as expressed above.

Any advice greatly appreciated. Its a solid stone town house (1820s) - so I want to get it right.

Thanks

 

[foxhole]

Absolute nonsense , foam is not going to warp or bend a frame.

 

[JohnD]

I have vertical sliding sashes, and I foamed them by drilling several holes, around 200mm apart vertically. First I injected in the bottom one, and waited until it had expanded enough to be seen in the next one up. When it had stopped expanding, I injected into the next highest. It was therefore able to expand upwards without restraint in the gap, until I had filled the entire gap. By injecting alternately left, right, top, bottom I did not need to spend much waiting time. A piece of duct tape over each hole prevents it dripping out. After a couple of holes, you have a fair idea of how much foam is needed. When their is a big gap in the brickwork it will need more, to fill it. A small spray gun of water will make it skin over. If you dampen the wall first it will stick better and expand and set quickly.

btw cling film, taped into place, is very good for preventing errant foam from sticking to the frame or wall.

You need to tape the outside securely to prevent foam oozing out of any gap, it is quite tiresome to remove. For safety, I remove the sashes to prevent any foam getting into the sliding joint and cementing it solid.

 

[Rad1o]

Use expansion foam and have a hand spray bottle with water ready. If / When foam expands too far or drips onto anything spray the water onto the foam. It will slow the expansion and start to seal the surface by "cooling" the foam. Once cured just cut the excess to size.