Venting Through Parapet Walls
I’m a contractor in Philadelphia and rehabbing a townhouse in Philadelphia (CZ 4). I have a new torch down modified bit roof over a self adhered underlayment – I’ll be installing a roof deck on sleeper systems in the spring. There are parapet walls on the sides and back of the roof, but no great way to adequately vent the roof without chopping up the deck space.
My question is if I can vent through the parapet walls, using strip soffit vents towards the top of the parapet – I’d carry the metal capping down to protect from the elements but still let it breath. I can’t put any roof vents in the center of the roof but could put a couple near the front of the house (high side of roof). Am I inviting more problems with the strip vents? Would a couple solar powered vents at high side and strip vents towards the lower side work? Do I need to knock down the house and start over?
I can drop the ceiling down a few inches and get about 4″ of air space above the insulation at the low side and ~10″ on the high side. I’ll be using a smart vapor retarder, all my ceiling fixtures are in lesco boxes, and I’ll be running multiple blower door tests so I don’t anticipate too much moisture laden air reaching the roof decking/insulation. I really don’t want to use spray foam (for environmental reasons, and durability should a leak occur), and am not really able to do a warm roof at this stage.
I’ve read all the articles and blog posts about venting flat roofs, talked to architects, roofers, engineers, inspectors, etc. My architect tells me that it’s not that big of a deal if the assembly can dry to the interior, and the ceiling will be air sealed and tested. This is my personal house so my tolerance for new techniques is a bit higher. Does anyone have any experience with this??
Thanks in advance,
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