Installing rigid insulatlon
I’m in marine climate, 4-C, a couple of miles from Puget Sound in Washington.
So far I have osb sheathing over 2×6 studs at 24” OC. My plan: one inch of rigid EPS (the white stuff mostly due to lower cost) with foil backing (towards the inside to reflect heat back?), tape and seal with flashing and screen to keep bugs from making new home, then 1×4 furring strips to create rain screen channel and boost R factor. I have one gable end without OSB so would have to extend EPS or fur out the plane two inches after covering with asphalt felt.
Sound like a good plan?
Still thinking about interior stud cavity insulation but no interior vapor barrier.Leaning toward a ductless heat pump and certified wood stove for heat.
Really enjoy this site—intelligent exchange and great ideas. FYI, for local codes and best practices the WSU energy extension guys and gal and have been very helpful.
Bjorn
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Replies
Bjorn,
I don't know why your gable has no OSB. If it were my house, I would certainly sheathe the gable.
Your plan is OK, although the insulation levels aren't great. Thicker foam would give you better performance, but the 1 inch of EPS is adequate in your climate.
Only one point: the shiny side of the EPS goes out, facing the rainscreen gap. A radiant barrier is useless unless it faces an air space.