Insulated headers with exterior insulation
I’m working on an addition/energy retrofit project and have been looking for clarification on using insulated headers with exterior foam insulation.
I’m planning on 4″ of exterior foam insulation, which will cover the house wrap, sheathing, and 2×6 wall framing.
Is it permissible to insulate the headers when using exterior insulation? I’m set to let the wall dry to the inside and am concerned that sandwiching foam board between the headers will leave the outboard header and sheathing “trapped” with respect to drying potential. Given the small areas of the headers and proximity to openings, maybe I’m overthinking things, and any moisture in these areas will migrate to surrounding lumber, which has drying potential.
I’d appreciate any clarity on my options! Thanks!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
pvo88,
Because of the amount of exterior insulation outboard of the sheathing and header, they will never be cold enough to accumulate moisture, and any incidental wetting can dry to the surrounding lumber.
Thank you for the reply!
What type of insulation do you have planned for the rest of the wall cavities that are not along the header? If you do an integrated structural rim board that is 2x, and your wall is a 2x6, you will have about 4” of room in the header pocket. If you are doing BIBS or loose fill insulation in the other wall cavities you could also do that same technique in these header pockets. No need for impermeable rigid insulation. The old technique of sandwiching XPS between two 2x’s is outdated. I think Steve Baczek has a video showing his updated version of an insulated header pocket. The APA has a free guide on advanced framing techniques, integrated headers is one of them:
https://www.apawood.org/publication-search?q=m400&tid=1