Floor and ceiling insulation for a cabin/studio in British Columbia
I am going to be building a small (8×13) cabin (studio) to go in my backyard near Vancouver, BC. It is going to get used regularly in the summer, and occasionally during the winter. When not being used in winter, it will remain unheated, and when in use, we plan to use a radiant oil filled electric heater. It will be a post and beam structure, and I have a large supply of 1 1/2′ T&G cedar that was reclaimed from a panabode cabin that will be my walls.
For the floor, I am planning to do an ordinary floor with PT 2×6 joists (set on concrete blocks about 8″ above ground), 3/4 ply over the joists and then some hardwood finish flooring inside.
The ceiling will be a cathedral ceiling (with a sleeping loft) and the roof will be metal, pitch 10-12.
I would like to insulate the floor and the ceiling, so it holds a bit of heat when being used in winter (there is no point trying to insulate the walls) I originally considered using mineral wool between the floor joists, but after a bit of reading on this site, I am thinking XPS over the subfloor, with a second layer of ply on top, is a better way to go.
For the cathedral ceiling I am also considering XPS, but am not sure about moisture management. if the studio stays cold for weeks on end in winter, through rain and freeze thaw, where will moisture build up , and also over the cathedral ceiling.
I have read numerous articles here on issues about moisture management in cold/damp conditions for heated houses, but I haven’t seen anything about what happens when the interior spaces are left to get cold. Does it change the moisture management strategies, drying from inside out, or outside, in, or what materials would be best?
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