How to ventilate a hip roof
We are going to be replacing the roof on our house as part of a project to make the house more energy efficient as well as an addition and remodel. I live in NJ – a little bit north of central, so we have pretty good swings in climate between summer and winter. The house has a shallow hip roof, and the house is 42′ wide and 26′ deep. There are nice large overhangs at the eaves, and we will be putting in lots of venting there, but the question is what to do at the top. There is an old existing power fan, two passive vents and a ridge vent. My guess is that the ridge vent is not very effective on it’s own due to it’s small size and the pitch of the roof, but I also think that the power fan is probably being short-circuited in it’s effectiveness because of all the upper passive vents.
The sheathing in the attic is all molded because a number of years ago, someone closed up the vents at the eaves. We’re thinking about replacing the sheathing with ZipSystem roof sheathing. We’re going to do flash and batt in the attic – about 2″ of closed-cell foam and then R38 of batts on top.
I’ve attached a picture so you can see the roof. Should I leave the fan in and close up the other vents, or just do passive venting? What’s the best strategy?
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