Insulate exterior wall from the inside.

[kleptoman]

Yes, the constant question in this forum. I can't figure it out no matter how much I read about it.
We have bought a house from '23 and are now getting into making the bathroom bigger.
We will take a large part of another room that was once a kitchen. One whole wall is against the outer wall. How do we insulate now?

And in the old kitchen that now becomes part of the bathroom, there was a ventilation hatch for the old pantry. How do I seal this in the best way? What should I fill it with to avoid moisture? It is a wooden house that was plastered in the 60s.

 

[etiol]

You frame the outer wall with 30 cc, insulate it, and then add plastic (vapor barrier). After that, you put a 15 mm plyboard and then gypsum board, using staggered joints, then you have a sturdy wall that you can tile and screw into as you wish. The inner walls are done the same way, but with no plastic on these. You seal the vent with regular insulation and on the inside, you put plastic which you tape securely, and then gypsum board. Eti..

 

[kleptoman]

You frame the outer wall with 30 cc, insulate and then plastic (vapour barrier). Then you put a 15 mm plywood and then drywall, here you use staggered joints, then you have a sturdy wall that you can tile and screw into as you wish. And you make the inner walls the same, but no plastic on these. You seal the vent with regular insulation and on the inside you put plastic which you tape securely, and drywall. Eti..

Awesome! It was mostly the vapor barrier I was wondering about! Thanks for the help!

 

[Tor H]

Should there really be a vapor barrier if it's going to be a bathroom and waterproofed afterwards?

 

[Dalbotant]

Should a vapor barrier really be put there if it's going to be a bathroom and then sealed later?

Nope, then there will be double sealings, and that is not recommended. Whether one should insulate a house from that time at all is very debated, you probably need to read up a bit and then come to your own decision.