Air sealing interior and exterior in small cabin/sauna
We are in the process of building a small cabin (one room with a single slope vented cathedral ceiling) in zone 6B, heated exclusively with wood and no AC in the summer. After living in the cabin full time for a few years, it will eventually be converted to a Sauna. Because of that, we are installing foil faced polyiso on the interior (walls, roof, and a site built SIP floor) and meticulously air sealing the interior. In addition to the polyiso, we are putting mineral wool between the walls and roof framing.
Should we also focus on air sealing the exterior sheathing, or in this instance, is a thorough interior air sealing enough? I’m having a hard time wrapping my head around wind washing being an issue between 1/8″ cracks in sheathing, but perhaps it has a greater effect than I realize.
Thank you,
Mat
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
It's always worth air sealing the exterior sheathing, which provides a more robust and reliable long term air seal than most interior air sealing approaches (which are also always worthwhile.)
Rainscreened siding is also always worthwhile (in locations wetter than the Atacama desert anyway... :-) ).