non vented Hunter Cool Vent?

Guest User
7/3/2017
I received a bid for our first metal roof & would like your opinion. We have a beach cottage 2 blocks from the ocean & have decided on aluminum 5V crimp. We have 3/4" tongue & groove roof deck with NO plywood on top of that. Inside we have exposed T&G, open rafters, no insulation. Outside the rafters are exposed open end (no soffit). We don't want the roof fasteners to penetrate the thin 3/4" T&G & be visible in the ceiling. Definitely in a hurricane zone, so will need to add 5/8" plywood so screw length will pass code. Here is the proposal we would like to go with: Remove existing down to T&G sheathing, install one layer Hunter 2.5" Cool-Vent, one layer self adhered water proofing underlayment, install .040 pre-painted Kynar 500 light gray aluminum 5V. The Cool-Vent has a 1" air space sandwiched between 1" foam & 5/8" plywood. We badly need at least 1" foam insulation. A/C runs non stop in summer temps. MY CONCERN IS: the proposal mentions nothing about venting the 1" air space. Is it a waste of $ to pay extra for the air space? If it's not vented at the ridge & eaves will it help at all with inside temperature? Without venting, could moisture get trapped in the air space & cause problems? I see that ridge vents are available for metal roofs, but reviews say they clog-up pretty fast & slow the airflow. Is there a good way to vent the 1" air space along the eave since there is no soffit? Would appreciate your thoughts. thank you
Todd Miller
Isaiah Industries, Inc.
7/4/2017
There is value to the airspace even if it is not vented. It will act as a thermal break, and that is good for energy efficiency. If you put down a vapor barrier prior to the Hunter Panel, then you would be able to minimize the amount of moisture getting into the Hunter Panel, which would be a good idea if the panel is not vented. Would it be best to vent it though? Yes. There are good ridge vents available for metal roofs. As far as intake, the roof could be extended out a bit with a new fascia and bring air up into the vented areas of the Hunter panels through the soffit ... or you could put screened vents in the top of the fascia to bring air in.

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