0 Helpful?

Flash and Batt foam thickness

I'm in NJ climate zone 5 and have a project with an installed falsh and batt with 1" closed cell foam and Roxul batt in wood framing. I usually spec 2"+ but would like to avoid ripping everything apart and spraying more foam. Is there a chart/rule-of-thumb anywhere showing wtih of foam based on climate zone averages or any specific data to justify thickness besides doing a calc? This seems like a case where it would probably be ok but with a small chance for a big problem??

Asked by MMargulies
Posted Jan 25, 2013 10:33 AM ET
Edited Jan 25, 2013 10:35 AM ET

Tags:

1 Answer

Select your preferred way to display the comments and click "Save settings" to activate your changes.
1.

Michael,
Relax -- your walls should be fine.

The guidelines you are looking for can be found in either of these two articles:

Calculating the Minimum Thickness of Rigid Foam Sheathing (Look for the paragraph with the headline, "What about flash-and-batt jobs?")

Why Flash and Batt Makes Sense ("According to building scientist Joseph Lstiburek, flash-and-batt installations require at least 1 inch of spray foam in climate zone 5, 1 1⁄2 inch in zone 6, and 2 inches in zone 7.")

Answered by user-756436
Posted Jan 25, 2013 10:40 AM ET

Other Questions in Energy efficiency and durability

Filling a sunken floor and laying Tile.

In GBA Pro help | Asked by Sammie Hodges | Feb 20, 17

New home build in Iowa (Climate Zone 5)

In Building Code Questions | Asked by N/A N/A | Feb 20, 17

Need advice on insulating walls

In General questions | Asked by Martin Holladay | Feb 20, 17

Roof insulation for a West Baltimore row house

In Energy efficiency and durability | Asked by Timothy Werner | Feb 20, 17

Building a "pretty good house" in Southwest Michigan

In Energy efficiency and durability | Asked by Brant Quinn | Jan 6, 17
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!