ZIP System R-Sheathing
Steamr1
| Posted in General Questions on
I am trying to determine in the zip r 3 panel will be enough to warm the surface?NC mtns. Zone 5..I will insulate w dense pack on the inside…will the r 3 be enough to warm the condensation surface?thanks!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
Hi Lee,
I just spoke to Steve Baczek (architect, building scientist, and FHB/GBA author) about using ZIP R. He uses it often on high-performance homes. I was curious how it was similar and/or different than installing insulation on the outside of sheathing from a moisture management perspective--as you know, with ZIP R panels, the foam insulation is inside the OBS.
According to Steve, the short answer to your question is to follow the advice in this article (Calculating the Minimum Thickness of Rigid Foam Sheathing) as if you were installing exterior rigid foam insulation over sheathing.
That, and be diligent about water management and air sealing. It's Steve's thought, and most experts agree, that if you are preventing water from getting into the wall (from rain and snow melt) and air infiltration and exfiltration from the house, and are close to recommended R-values for cavity and continuous insulation, vapor drive is not a major concern.