Insulate between joists. Foam sealant?

[Rooney]

I am going to renovate one of the rooms upstairs and when I removed the baseboards, there is a 1-2 cm gap between the floor and the drywall along the entire wall (not an exterior wall). When you look in/down, you can see that there is no insulation in the floor cavity towards the downstairs. Additionally, you can feel a bit of cooler air flowing out of the gap from the floor cavity. I am wondering if I can spray 1-2 cans of foam sealant into the gap? Partly to soundproof a bit (the living room is below) and partly to prevent the cold draft. The floor cavity is almost 20 cm, so to push in fiberglass/rock wool in the gap feels like it would take quite a while to fill up. The house has passive ventilation and was built in 1973.

 

[mexitegel]

Split regular insulation into thinner strips and poke down with something like a try square, similar to how you would draft windows instead.

Foam sealant is a terrible invention.

 

[Strip]

The strength of expanding foam sealant is not entirely unimpressive, so I definitely wouldn't attempt to do it without knowing for sure that there's enough space for the foam to expand. Glue a small strip of wallpaper or something similar, so at least you avoid the draft.

 

[Rooney]

The strength of expanding foam is not entirely unimpressive, so I definitely wouldn't attempt it without knowing that there is certainly enough space for the foam to expand. Glue on a small piece of wallpaper or something similar, at least that way you avoid the draft.

It's probably 60 sqm with uninsulated floor joists, so there's likely enough space. I might still do as mexitegel suggested and put in regular insulation even if it might not fill up as much.

 

[mexitegel]

Should you for some reason need to tear into the joists at some point in the future, you will swear many long oaths over the sealant foam

 

[Peter2400]

We also had problems with leaky and poorly insulated flooring, there's some mention of it in this thread
https://www.byggahus.se/forum/threads/lite-varmare-golv-men-hur.290817/#post-2655270

 

[Björn Melander]

Just wanted to add that foam sealant is ineffective when it comes to soundproofing.

 

[SideshowBobBuilder]

Just want to point out that foam sealant is crap. Stay away. Use more natural products than that horrible substance.