We just completed having a house in built NH in the the Upper Valley. There is unfinished space above 3 car garage. The floor is insulated, but the walls and ceilings are just studs and rafters (except the wall connected to the main house, which is insulated). This unfinished space has multiple casement windows. Because the eventual (5+ years from now) aim was to convert into mother-in-law quarters, there is no ventilation in this space, and the roof is a “hot” roof, and there are not eaves vents or vents elsewhere. The space is hot in summer, freezing in winter. Our attic in our old house has fans that turn on in hot weather. There are no such features in the this space.
Question 1: Can I leave the space unventilated? or will leaving it as constructed damage the structure (damage roof? or accumulate moisture? or other problems?). I could leave the windows open, with casement windows a fair amount of rain would enter the space.
Question 2: If ventilation should be added, how would this best be accomplished.
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