Insulating new construction home with no exterior rigid foam
Okay smarties, here is my scenario:
-I am Building a new home that is currently in the framing stage. 2×6 studs with Forcefield Sheathing (essentially same as ZIP).
-I am in in Climate 5 (iowa)
-My home is a California style architecture, 1.5 story, pitched roofs (now I realize why this is better suited for CA-vented roofs better option in Midwest!)
-My initial goal and how I came across these articles was to prevent mold (still is)
-Second goal was to have healthy IAQ (as much as possible) I have spent a considerable amount of time researching paints, caulks, indoor furniture, etc but now realize how important ventilation and building envelope is
Anyway-I UNDERSTAND the best option for a building envelope in Climate zone 5 is to do Exterior Rigid Foam (EPS preferably) equal or greater than an R value of 7.5 with seams staggered. BUT I cannot afford it! AND no one even understands what I am talking about! No experienced installer means more money and it may not be done right!!! Also, concerned about ants with rigid foam…would actually prefer Mineral Wool on exterior in a perfect world.
Also, should note that I also understand closed cell foam would also be a good application when no exterior insulation HOWEVER I am absolutely opposed to spray foam.
SOOOOO, thinking my option is to make sure I have a rain screen with 1×4 furring strips on exterior of sheathing and then doing
A) wetblown cellulose between 2×6 studs, Membrain or another smart vapor retarder over that then my drywall with eggshell paint…..
B) same scenario as above but with JM Spider insulation….
I understand I will still get moisture on interior side sheathing but gap should help it to dry out???
I have more questions on roof insulation too but thinking I will save for another post!
THANK YOU for any help or insight! Cost is a factor but I also want a building envelope that will last, be healthy-ish and prevent future issues.
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