Sheathing – plywood vs Eclipse Foil Faced OSB
We are looking to build our next home thisupcoming spring and I am trying to decide what sheathing I should use on this project. The first house we built was a PU SIP (thermocore) home and our current home is a more standard 2×6 stick built home with OSB sheathing (2″ PU spray foam then blown cellulose for walls and attic ceiling). We have been surprised that our heating/cooling bill on our current home is almost the same even though we have almost doubled the sqft of our SIP home – although we are protected from western winds during winter (northern MI) and have significant shade in summer (nestled in a maple forest) at our current location which was notthe case previously. We will have a similar setup with slightly less summer shade in the next house, and I had originally planned to switch from OSB to all plywood construction. (Sheathing and subfloors). However, the Eclispse foil faced OSB has me interested. I am contemplating it for the roof sheathing and the wall sheathing – both with the foil facing inward. That is the typical method they recommend for the roof but they suggest using the foil face as the WRB on the walls. I don’t want to do that as I am worried it would prevent the wall from drying if I use 2″ of PU spray foam then cellulose again for the wall insulation – instead I am wondering if it would make sense to put the foil facing inward then spray the foam onto it and use Typar as planned for the WRB on exterior. Thoughts?
Also, I use Grace Ice and Water for the entire roof. If I use that on the exterior and the foil face is facing the interior, would that prevent the roof OSB from drying too?
Any thoughts or feedback are greatly appreciated! The price on this Eclipse sheathing is very attractive currently as it is about equal to plywood, but i don’t know if it will be best long term to go with it or stick with my original plan of all plywood construction this time around.
Thanks in advance – Paul
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