Does Anyone NOT recommend using Zip R3 in CZ 4 (Northern Virginia)?
We are working with an architect to design a practical and cost-effective ‘energy-smart’ located Fairfax County, VA (outside Washington, DC). I am not an architect, engineer, or building scientist, so trying to decide on a practical, energy efficient, above-code (tight envelope and higher assembly R values, but not NZER or Passive), durable, cost-effective wall assembly has proven harder than expected. The architect (along with my HERS rater and independent HVAC designer) are pushing me to use Zip R3 as the exterior sheathing, but when I talk with most custom builders in my market, they look at me like I am from Mars and/or immediately double the total construction budget!
I can get into more detail of the wall ‘sandwich’ (inside out – 1/2 gyp, 2×6 24″ OC, blown cellulose plus 1″ CCSF, Zip R3, rain screen, hardie plank) but at this point all I am really trying to find out is whether the energy efficiency experts consider adding Zip R3 (with its’s measly 1/2″ of foam) in my CZ is worth its “thermal bridging, air barrier, vapor barrier” bang for it’s higher buck before capitulating to the builder’s ‘go-to’ (and higher profit) solution of using OSB sheathing wrapped in a WRB.
Don’t get me started on trying to find residential builders and framing subs willing to use 24″ OC framing, 2-stud corners and other advanced framing techniques.
And, speaking of water vapor, has anyone experienced condensation issues (winter or summer) issues when combining hardie plank with Zip R3 sheathing in CZ 4. trapping water vapor between the that