Using ZIP-R12
mmoogie
| Posted in Energy Efficiency and Durability on
Hi folks,
I’m building a 1500 SF cabin for a client in Upstate NY (zone 6) and am contemplating what to use for continuous exterior insulation. I was giving ZIP-R12 serious consideration, but when I called my supplier he says that people have a) been having a trouble getting it at all, and b) having issues with door and window stability when using it. Anyone here been using it and what has your experience been as for as availability and movement stability (window racking, etc).
Steve
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Replies
Before committing to the Zip R12, you should do a search on the GBA questions section. Many useful comments from people that have specced it or used it. Biggest alarm bell is improper nail setting which compromises the structural value. Expense and bonding failure of the foam are two other notable issues mentioned.
One work around could be to use let in bracing to provide the basic anti-racking required for your wind conditions and to meet code, then apply the R12 if affordable and approved. Some miss nailing would have less effect. Or brace then sheath with used XPS - new XPS if the low GWP stuff is available- or polyiso though the up state climate range might make this a lesser option thermally. Tape or WRB, add rain screen furring and siding.
Engineering obviously needs to be done to show sufficient strength with such an approach, so do not take my word for it. These are just suggestions for getting your thinking out of one track.
I've also been considering 2 or 3" of rigid rockwool on the outside of normal 1/2" sheathing. I'm planning on a rainscreen no matter what the rest of the wall build consists of. One factor that is weighing against the zip-r is the foam. I would prefer to minimize the use of foam, but I also want to keep the build as simple and efficient as possible. The Zip-r is appealing because it is one trip around the shell instead of two.