Quote:
Originally Posted by Ecky
You don’t want to ventilate your heated or cooled air to the outside.
I can’t speak for elsewhere but in Vermont there are some disadvantages to finishing an attic. It’s what you’d called a “hot roof”, because no matter how well you insulate it, if there’s no vented space between insulation and roof, the roof will be warmer than the air around it and in winter you’ll get ice dams, increased risk of water damage and generally just far lower roof lifespan.
I’m being facetious when I say this, but if you want to finish an attic and turn it into living space, ideally you’d rip the roof off and build a new vented attic on top of your attic so your roof can be cold.
In summer, having a vented space between shingles/sheathing and insulation greatly improves thermal performance of the structure.
Think of your roof as just being a tarp or shield to keep rain and snow off.
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Thanks for the input, I'm not a builder, though I'm learning.
Would it make sense then to have the regular vents, sheet the inside of the rafters (to make a vented "dead space" so to speak), and then add furring strips inside of the sheeting, insulate, then finish? obviously this is a lot of extra expense/space lost, but is it worthwhile at all? I know that box stores sell room-in-attic rafters, so is the intent to be strictly unfinished rooms, or do they take something like the approach I suggested?