Open cell or closed cell in walls in hot/humid Zone 2?
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Hello
We are building house in New Orleans and here is our proposed assembly. We were curious if anyone had insight with respect to closed vs. open cell foam here?
hardie board clapboard
1x vertical nailers (rainscreen)
Zip sheathing
2×4 studs with spray foam to code (R13)
sheetrock
thanks!
Brad
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Replies
Designing homes in golf areas, I specify PT CDX (at least the first 4'), with taped seams, Tyvek over the sheathing and rigid foam on top of the sheathing and staggered seams. If the rigid foam is taped with approved tape, it becomes a 2nd WRB.
You could decide based on material and installation costs between a) 3.5” R24 ccSPF wall, and b) 3.5” R13 ocSPF + 1” R5 min. rigid foam for an R18 total wall. Including the Hardie boards over the rainscreen is a good wall assembly.
Here is a good calculator to play with and figure out what is best for you… https://www.ekotrope.com/r-value-calculator
Thank you Armando, I appreciate your input!