2x120mm Outer Wall

[empame]

I am about to expand my house by about 35 square meters.

The foundation is almost ready, and it's time to start with the walls, etc.
My thoughts are on the exterior walls. I can get "almost" unlimited 45x120mm timber. Is it too thin with 120 standing and 45 lying flat?
Could you then build with 2x120mm standing slightly offset?
This would provide 240mm insulation which sounds good, but are there any drawbacks to not using 45x45 lying flat with insulation?

 

[hurk]

Hello! The inner layer with horizontal 45x45s is good for electrical wiring, etc., without having to go outside the plastic. Which, by the way, should not be more than one-third out into the wall.

Apart from that, it is quite OK to lay double, staggered layers of 45x120..! /h

 

[empame]

OK. So the plastic is usually placed between the 45 and 170mm?? Where should I place the plastic in my case? Directly inside the drywall or inside the av. osb?

 

[Gladh]

In your case, which is not recommended, I would put the plastic between the drywall and the OSB, to minimize the "exit hole" in the plastic when you puncture it by screwing/nailing into the walls...

 

[empame]

It will be standing 120 and lying 45 both externally and internally. It seems to be better than Double standing 120.

 

[Egon84]

Why not standing 120 with horizontal 120 on the outside and horizontal 45 on the inside? If, as it seems, you had access to cheap 120, it would provide much better insulation that way.