EI30 walls

[Cervus Elaphus]

Staple gun I use for wind barrier

 

[Rolle85]

Oki, thanks everyone

 

[Rabbithole]

Is cell plastic the cheapest insulation? How thick is the thinnest?

Glass wool is the cheapest, cell plastic is available from 10mm but thin doesn't make much difference.

 

[Rolle85]

Okay

 

[Rolle85]

The house is 30m2, i.e., 7.5m x 4m. The question is how much extra it would cost to install cellplast with, say, 20mm thickness in the house?

 

[Rabbithole]

Just calculate the surface area needed. Calculated with approximately 55m2 -> 77 sheets of 600x1200

Prices for S80 Eps at Byggmax are approximately:
1400:- for 30mm 25.5:-/m2
3700:- for 100mm 67.3:-/m2

Floor: 2000:- for 100mm
Ceiling: 2000:- for 100mm

But remember that foam plastic does not help with your fire protection. Glass wool is fine, but then you have to frame.

 

[Rolle85]

I was checking on Byggmax. The insulation foam seems to only come in the size 120x60cm. Therefore, I need two such pieces to reach the ceiling. For a 7.5-meter wall, you need 25 sheets. This would mean a cost of about 440 SEK if you choose 30mm thick insulation foam. Seems very cheap if this can provide any insulation, right? The reason I want to go relatively thin is to not take up too much space inside the house. How big is the insulation difference between 30mm and 50mm insulation foam?

Procedure:
Do I put wind paper on the inside of the wall first, then insulation foam, and then plasterboard?
Do you screw the insulation foam into the wall or is it typically glued?
Can you screw the plasterboard into the insulation foam or do I need longer screws that go through both plasterboard and insulation foam into the pine wall?
I don't want to create moisture problems in the wall.

 

[Rabbithole]

Wind barrier is not needed if you're using foam insulation. The easiest approach is to apply a dab of foam adhesive so they stay in place while you're installing the drywall.

Use long screws to clamp the foam between the drywall and the wooden wall.

The insulation is proportional to the thickness, so 50mm provides 60% more than 30mm.

 

[Rolle85]

Hmm okay. Thank you!

 

[Rolle85]

But what happens when cold air meets the outside of the foam plastic? Does condensation then form between the foam plastic and the gypsum board, thereby creating mold?

 

[bossespecial]

I'm somewhat questioning the use of polystyrene in the construction. It seems a bit contradictory to use an extremely flammable material in a fire-rated wall?

 

[Rolle85]

Hmm what are the alternatives if you don't want to build very thick insulation and don't want to build studs?

 

[Rolle85]

I saw that there are insulation boards at 45mm. With what do I build up the different wall layers then?

 

[kulle]

Ground board stone wool might work
https://www.bauhaus.se/markskiva-38-isover-stenull-50x1000x1200mm-50-1-2m.html

 

[Rolle85]

But aren't there such boards for walls and not 180kr/m2.
How about this one:
https://www.byggmax.se/isolering/mineralull/isoleringsskiva-p16204