Insulating a brick wall from the inside
We have a 100 year old row house in Montreal, (zone 5000). Most walls abut the homes on either side, but we have a bump out in the back with two exposed walls. The walls are two bricks thick, (I think), with plaster on the inside, and I think a layer of drywall on top, (judging by how the walls are actually proud of the original baseboards).
The walls in question are in our bathroom, which gets quite chilly. I’d like to add foam board insulation on top of the walls, and then drywall on top of that again (we can live with the resulting deep sills in the windows).
My concern is moisture build-up between the foam and the drywall due to condensation in this damp environment. Should I install furring and have some sort of small gap at the top and bottom to allow moisture to evaporate? Or should I just make sure it’s totally hermetically sealed by using a lot of adhesive? Any other suggestions?
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