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Vapor diffusion port – GreenBuildingAdvisor
- December 18, 2025
- Posted by: sherwin@eyeconz.com
- Category: Uncategorized
Doing a remodel on our house in Sacramento Valley, California (climate zone 3b), and making a conditioned/unvented attic with a vapor diffusion port. HVAC system will have dehumidifier and will monitor attic humidity and set dehumidifier to operate/maintain RH in the attic in the 35 – 40 RH range in the fall and winter. Roofer was not careful and put at least 7 roofing nails through one edge of the vapor diffusion port membrane (Delta Vent SA with vapor permeability of 50 perms). Do we need to remove ridge vent and upper course of shingles and replace the entire self adhered vapor permeable membrane? Or can we try patching it by running another layer of Delta Vent (~ 1 foot wide) over the ~ 10 foot section that has the roofing nail holes? Patching would mean 2 layers of Delta Vent SA in the patched area. I don’t think we can just leave it as is. Thanks for expert advice
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