Hello forum!
I am renovating an old outbuilding on the property, about 45 sqm. The house currently sits on an insulated concrete slab. The walls are framed with 120 studs. On the outside, there are two layers of cladding, one standing and one lying (they attached the lying directly outside the standing instead of replacing). There is a 25 mm air gap between the studs and the cladding, but there is no wind barrier paper. The roof is open to the ridge with 220 mm rafters on the ridge beam, then there is sheathing, roofing felt, and metal roofing. I will install 120 mm glass wool insulation in the walls and 195 mm in the roof. The space will be heated to around 17-18 degrees year-round. Should I install a vapor barrier in the form of plastic, or can I manage without?
I am renovating an old outbuilding on the property, about 45 sqm. The house currently sits on an insulated concrete slab. The walls are framed with 120 studs. On the outside, there are two layers of cladding, one standing and one lying (they attached the lying directly outside the standing instead of replacing). There is a 25 mm air gap between the studs and the cladding, but there is no wind barrier paper. The roof is open to the ridge with 220 mm rafters on the ridge beam, then there is sheathing, roofing felt, and metal roofing. I will install 120 mm glass wool insulation in the walls and 195 mm in the roof. The space will be heated to around 17-18 degrees year-round. Should I install a vapor barrier in the form of plastic, or can I manage without?
You are just in the "borderland," for whether it's needed or not. It also depends a bit on what kind of wall/ceiling covering you plan to have. For instance, if you were to have drywall with some vinyl wallpaper, you'd be fine. But in such a cabin, you certainly want to avoid drywall. On the ceiling, I can imagine you'd want regular wood paneling. Then there's a slight risk of condensation in the insulation.
I understand if you’d prefer to avoid plastic for the sake of the indoor climate. But there are different types of vapor barriers that are not as tight as plastic. Such a cloth, of some kind, is what you should have. Unfortunately, I can't help you with the name of any such material.
I understand if you’d prefer to avoid plastic for the sake of the indoor climate. But there are different types of vapor barriers that are not as tight as plastic. Such a cloth, of some kind, is what you should have. Unfortunately, I can't help you with the name of any such material.
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