Insulating flat roof with 7" cavity with roof tear-off

Hot-dry climate. Roofer removing all sheathing. Insulating from above while cavity is open. Plan for 5.5" open cell foam to the drywall and also covering dropped soffit area that houses ducts. There will be a minimum air gap of 1.5" (7"-5.5") between the foam and the deck at normal ceiling heights, about 1 ft over dropped ceilings.

Any concerns with this installation? electrical, mechanicals. performance etc?

Views: 1852

Reply to This

Replies to This Discussion

whoa didn't see all the comments until after i posted. sounds like you are on top of things. The OCF is an effective air barrier and will stop most all convective sources of moisture, and I don't believe you need to worry about vapor diffusion in that climate... So leaving the air gap sounds good to me. I'm a cold climate guy so I'd like a second opinion as well. Where's David Butler when you need him?



  • Add Videos
  • View All


Latest Activity

David N. Armington liked John Poole's discussion Two Part Epoxy and Repair of Structural Wood
2 hours ago
David N. Armington joined John Poole's group

Historic Home

Historic and vintage homes are significant to our cultural heritage, yet often lack energy…See More
2 hours ago
Seth Romme is now a member of Home Energy Pros
11 hours ago
John Nicholas replied to Rob Madden's discussion Blower Door Testing on Energy Star v3 home
"So you have a slab on grade home, duct work in the attic?"
Diane Jackson posted a photo

"Drive Home"

Addison Homes spent a fun day with a film crew from the National Association of Home Builders. We…
Paul Raymer posted a blog post

Healthy Home Evaluator Training

Fall River, MA     October 13, 2016…See More
Diane Chojnowski updated an event

Better homes video series at Seventhwave

October 24, 2016 to January 26, 2017
Profile Iconseoeleczo and Parfait Pouliotte joined Home Energy Pros

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service