It's blowing in. What should I seal the gap with (some foam sealant, caulk, gypsum mortar)?

[Klicka]

I have removed the wallpaper in a room upstairs. And I see that the corners are not taped with mesh. There are gaps of a few millimeters in each corner.

I feel cold air coming through the gap in the corner. I don't want thermal bridges when I re-wallpaper later.

What should I seal the gap with (some insulation foam, sealant, plaster)?

 

[norrbottenstorpet]

Foam sealant or flexible sealant, not gypsum mortar (unless it's a stone house).

 

[Klicka]

Foam sealant might harden faster but worse for health?

 

[jarlh]

fogskum may harden faster but worse for health?

What is the difference, considering health?

 

[JOW]

It will probably be difficult to get foam sealant into a crack of a few millimeters, use acrylic/latex sealant, paint over.

If you want to address the root problem, you need to open up the wall.

 

[JOW]

Jahrl: Isocyanates, search for it.

 

[norrbottenstorpet]

Nowadays, there is plenty of isocyanate-free sealant foam. Moreover, it is precisely during curing that isocyanates are formed. Cured foam is harmless.

If you use a sealant foam gun and nozzle, it's no problem to lay a couple of mm thick beads either. But on the other hand, we are talking about two mm; it's hardly going to create any thermal bridge worth mentioning with acrylic sealant either.

 

[cpalm]

Besides what JOW says that it might be difficult to get foam into such a narrow gap, I would, depending on the material/construction, be a bit cautious with foam sealant. The risk is that it expands inside the construction and causes undesired effects.