Remote cabin exterior wall design
Questions on remote cabin exterior wall design. I am building a small cabin, off grid in a remote location – Yukon Canada (cold dry climate). Not for full time habitation, but I suppose that could change in my future or with a with a different owner. Wood heat only, small solar to run LED lights, 12v stereo, no running water. Dimensions 16′ x 24′ (2 stories). I would like to minimize the exterior wall thickness as the interior space is not especially large to begin with. Cost and ease of construction are major planning considerations. I would like to use the exterior sheathing as the “siding”- 4’x8′ OSB installed vertically (stained or painted), then add 1″x 2″ batten boards affixed vertically on 16″ centers to the underlying wall studs – to give the cabin a board and batten facade.
Plan is 2×6″ stud wall on 16″ centers. Insulate stud cavity with Roxul Comfort Batt 5.5″ (R22). I would run a poly vapour barrier on the interior affixed to the surface of the stud. I would affix 1/2″ plywood directly over the vapour barrier fastened to the studs – this will be the interior wall (no drywall). No wiring or plumbing in the insulation cavity. Ideally I would like to address thermal bridging for the stud wall – I am wondering whether I could install Roxul ComfortBoard IS (insulation sheathing) 1.5″ against the exterior surface of the studs and then install my OSB sheathing/siding directly on top of the Roxul Comfortboard IS (no furring) – screwing the sheathing through to underlying studs? Essentially sandwich the Roxul IS Board between the sheathing and the stud. Basically I’d like to use a single sheathing layer and have it also be my exterior siding AND I’d like to deal with thermal bridging. Will this work?
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Replies
J. Bishop,
1. I suggest that you use T-111 for your cladding rather than OSB.
2. Remember to install Z-flashing at the horizontal seams of your exterior cladding.
3. It's essential to pay attention to airtightness when installing your interior and exterior cladding.
4. Your plan to sandwich mineral wool between your studs and your cladding is experimental. My guess is that the mineral wool will compress quite a bit where it contacts the framing. The plan would work better if you had two exterior layers: sheathing and cladding, with the mineral wool in between.
5. Don't forget that you need to include a WRB (housewrap) under your cladding.
Thanks Martin, yes to Z flashing and WRB, I simply forgot to mention them in the original post. And yes to air tightness detail. I will consider T111, although seems it wouldn't give me the board and batten look I was aiming for. I was thinking OSB with a premium grade exterior paint would provide a suitable and reasonably durable cladding. (All the T111 I have seen installed has grooving on the facing side. Could I install T111 smooth side out and then run my batten board strips on top to achieve the board and batten facade look?