Working With Zip-R Sheathing
We are looking at potentially installing a wall system that uses Zip R-sheathing. We are considering this approach to reduce the labor cost of installing continuous exterior insulation outboard of standard Zip sheathing and the associated detailing required at punched openings, etc.. I want to like this product, but I see some shortcomings. Here are the specifics:
The project is in a mixed heating/cooling region (climate Zone 5). The walls are 2×6 studs and filled with Rockwool batt insulation. Installation instructions for the Zip R-Sheathing recommend direct attachment to the studs. If we do this, the walls would have inlet bracing for shear. I have two questions about this method:
1) If my thinking is correct, doesn’t the back of the OSB in the Zip panel become the first condensing surface when installed directly to the studs? That removes a major benefit of continuous exterior insulation, which is keeping the first condensing surface above the dew point. What are your thoughts?
2) Assuming my logic for the previous question is correct, what’s the most cost effective approach to correct the wall assembly? A). Add sheathing between the studs and Zip R-Sheathing; B). Use a different air barrier/vapor barrier somewhere in the assembly (I’m not a fan of using the drywall as the air barrier…too many opportunities for holes after installation). C). Abandon the Zip R-Sheathing and go back to the original plan of using continuous insulation outboard of standard Zip sheathing.
I’d appreciate hearing your thoughts and experiences using Zip R-sheathing. Thanks!
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