Not always heated attached garage – vapor/insulation?
Garage is at the ground level (at grade), with one wall connected to the mechanical room, 3 other walls to the outside. Above the garage is living space.
There is a disconcerting debate on site over insulation.
The original idea was to use Rockwool everywhere (at the ceiling/wall.
The garage – by code – needs to have an air barrier from living space.
The garage is well insulated and will have a baseboard for the time when when it doubles as workshop. But it is not going to be kept at the same temp and all the time as the house. Zone 5.
The debate is where the air barrier should be (how to avoid the risk of mold/condensation) given that there will be temp diff between garage and the rest of the attach.
Closed cell foam is proposed instead of a Rockwool as one way to may be resolve it but I am not sure if it solves any problems rather than creates more.
Any suggestion? I tried searching archives but I am clearly not using the right words.
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Replies
orange_cat,
It's wherever the required vapour-barrier / retarder is that could be a worry. The air-barrier can be anywhere.
Treat the walls and ceiling / floor above as though the garage was a carport. So they should be built just like the rest of the house exterior - except they get no cladding. If you design them as though they were outdoors, they will be fine when the garage is occasionally heated.
Thank you, very helpful