Retrofit vented attic to… unvented?
Quick question for the board members… Currently in the prep phase for a second story addition to one part of our house, that will entail splicing into the existing roof for roof/wall flashing as well as some structural improvements to a few rafters..
The current roof structure is 2×4 rafters, sitting on the wall top plate with birds mouth cut… so… Effectively, 1-2″ of insulation if i’m lucky.
Was curious what you all would recommend…. My gut feeling is to ‘chainsaw retro’, but reading into codes (Ontario..), it’s unclear… Would it be possible to simply leave existing attic floor insulation as is, but then to slap on some exterior foam/roxul, with a vented layer above that, or does it call for removal and then reinstallation in a net’d form under the rafters….
It appears that if I were to go that route, I would need to add some ventilation supply/returns to that attic space, plus added heating, in line with a crawlspace like deployment…. All of which makes it feel like the cost effectiveness of the whole idea is laughable..
Alternatively, if someone were to just tell me to turn up the heat, go have a beer…. I’d be cool with that.. 😉
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