Deciding between Zip sheathing or taped ply
Still trying to decide this question.
Lets say the house I am building will take 70 sheets of wall sheathing.
I can get 1/2 CDX for $15.92 per sheet= $1,114.4 whole house.
Zip 7/16 is $19.34 with a first time users discount= $1,353.8 whole house
Then there is tape cost which we can assume to be equal.
If I use tar paper I probably save a few bucks with the CDX but if I buy a high performance wrap I probably am more expensive than Zip.
Any thoughts. My main concern would be the long term durability of the Zip. Will it still be doing its job in 30 years? I am doing a lot of work so factoring in saved labor with the Zip is of course a bonus but not as important as if I was trying to save every second and penny to make a schedule and budget.
thanks
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Replies
Joe,
Q. "My main concern would be the long term durability of the Zip. Will it still be doing its job in 30 years?"
A. Unless you make a gross error in your flashing details, of course the Zip sheathing will be in good shape in 30 years.
Factor in the cost of using your preferred housewrap. IIRC Huber (manufacturer of ZIP) advertises that there is little to no cost difference between their system and the typical (OSB/Plywood + housewrap). Don't forget that housewrap is supposed to be taped as well. ZIP system has a much longer warranty period (20 or 30 yrs for initial owner) vs that of typical Tyvek (7 yrs?). In my area of the woods just about every luxury build ($1MM+) uses ZIP.
Mid-low priced homes use the cheapest sheathing and housewrap they can find.
IMO attention to detail is what matters.
From a drying standpoint, CDX is superior to Zip. This difference may or may not be significant. Same for lapped (wrap) vs non-lapped (Zip). Both are good, rigid air barriers.
Fine homebuilding recently ran an article comparing different WRB solutions you might be interested in:
https://www.finehomebuilding.com/?p=386133
The image at the bottom has a general cost breakdown. You can add the 13 cents per square foot for Zip tape to the housewrap option to account for taping the seams (or a little less, depending on your tape preferences).
Note that the spray applied WRB seems to be the only one that includes labor costs.
Make sure you qualify for the Zip discount. Also try shopping around for a better price on the Zip.
Good point BrianVarick, rebate only available to liscenced contractors, which I am not.
In general, I prefer a rigid air barrier than a flexible one. Hence my preference for ZIP, all things considered. I have also been to their lab and seen the moisture tests they put the ZIP through; The bond of the polymeric coating (that is key to the air and WRB barriers in ZIP) to the OSB core is pretty amazing.
And my own tape testing (https://www.greenbuildingadvisor.com/article/two-wingnuts-describe-their-backyard-tape-tests), ZIP tape was a really strong performer in terms of the strength and resistance to wetting over time.
Peter