Metal roof venting (using battens)
Hi, I have an unvented air tight roof assembly. With R23 wool between rafters. And 4 inches of R20 rigid foam above roof sheathing.
I am installing a standing seam metal roof over the rigid foam and need a solid surface to attach the roof panels.
My plan is to install wood battens on top of the rigid foam, securing them to the rafters. Which will structurally hold the metal roof as well as create an air gap for venting.
My question is, its a fairly low slope, and I’m concerned about condensation under the metal roof not drying quick enough and the wood battens being vulnerable over time to moisture.
I am considering coating the battens with a water sealant ? Is this risky ? Not necessary ?
Thank you
Alex
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Replies
Metal roofing is often installed over battens, I wouldn't worry too much about it. The battens can only get damamged from constant water ingress, most standing seam roof profiles allow for enough air flow to dry up any moisture from night time condensaion even on low slope.
As long as your metal roof is not leaking water, the battens will be fine.
Make sure there is a synthetic underlayment in your assembly (required by all metal roofing manufacturers) and that your metal panels are can be installed over battens (not all are).