Helpful? 0

Flat roof, non vented — What about furred space for slope?

I am building a non-vented flat roof in CEC zone 8/ DOE zone 3-92705. Roof structure will be structural sheathing on 12" I-joist. For slope, sheathing over 2x furring strips (1/4"/12"). I have read all the posts about various ways to insulate.

If the actual roof is something like a 2-ply SBS membrane and the insulation under the structural sheathing is a closed-cell flash-and-batt system, should I worry about the spaces between the 2x furring strips used over the structural sheathing for slope?

This space will not be vented. Will this space trap moisture?

Asked by keith messick
Posted Fri, 03/14/2014 - 10:33
Edited Fri, 03/14/2014 - 11:40

Tags:

1 Answer

Select your preferred way to display the comments and click "Save settings" to activate your changes.
1.
Helpful? 0

Keith,
Q. "If the actual roof is something like a 2-ply SBS membrane and the insulation under the structural sheathing is a closed-cell flash-and-batt system, should I worry about the spaces between the 2x furring strips used over the structural sheathing for slope?"

A. No.

Q. "This space will not be vented. Will this space trap moisture?"

A. No. But make sure that the materials are all dry on the day when your spray foam contractor shows up.

Answered by Martin Holladay, GBA Advisor
Posted Fri, 03/14/2014 - 11:36

Other Questions in Building Code Questions

In General questions | Asked by eric michael | Aug 30, 14
In Green building techniques | Asked by scott schroeder | Aug 29, 14
In General questions | Asked by Dawn Roberts | Aug 30, 14
In General questions | Asked by Jeff Watson | Mar 9, 14
In Energy efficiency and durability | Asked by Randy Mason | Aug 30, 14
Register for a free account and join the conversation


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