EI30 walls

[Rolle85]

I am going to build a wall classified according to fire rating EI30. That is, I am going to build a small cottage of 30m2 that is uninsulated and which we will use as an extra house at the summer place.
The wall consists of 45mm thick pine only; can you put regular plasterboard directly against the pine timber, or do you need to have something in between to prevent mold or similar issues?

Best regards

 

[Rabbithole]

Normally you can do that, but the question is whether the downpour will make the plaster damp.

 

[Rolle85]

Should you put some vapor barrier between gypsum and wood? Construction plastic? Or are there sealed layers with insulating properties?

 

[Rabbithole]

There are pir insulation boards with gypsum if that's what you're looking for. However, the usual reason for a vapor barrier is only necessary in homes with a lot of insulation. Storage rooms, etc. normally don't need a vapor barrier as the humidity level inside is low.

 

[Rolle85]

It's a 30m2 house that we will live in during the spring and summer.
But drywall directly on the wood should work then?

 

[Rabbithole]

Yes, but if you only have 45mm planks, I think rain can reach the plasterboard and that's not good. I would probably put a piece of cellplast between the plasterboard and the wood.

 

[Rolle85]

Does construction plastic work too?

 

[Rabbithole]

Yes, it should, but are you sure you want the wall completely uninsulated?

 

[Rolle85]

Is foam board the cheapest insulation? How thick is the thinnest?

 

[justusandersson]

It is completely inappropriate to apply building plastic to an uninsulated wall. It can cause significant problems. Plastic should only be used in heated houses. It's better to use some form of asphalt paper.

 

[Rolle85]

Wind barrier?

 

[justusandersson]

AC 350 e.g.

 

[Rolle85]

Ok, how do you handle the joints for the paper? Nails, glue, tape with overlap?

 

[justusandersson]

Nail + overlap.

 

[Rolle85]

Okay