We are trying to maximize wall assembly R-value: Very cold climate in CO
New home construction: 2x6 ext wall with 2" of closed cell spray foam with the additional 3.5" of cellulose or fiberglass batt. I was thinking of going with Dow's SIS panel (1" R5.5), but I am reading from one of Robert Riversong's comments that the impermeability of the SIS panel (Polyiso) is a bad idea for our climate.
I admit, 2" of XPS allows better permeability but I thought we could save time with the use of the SIS panel and taping. We are in Frisco, CO and almost 10,000 ft. I am fairly certain we can keep moisture from condensing on the interior side of the SIS panel because of the flash and batt technique. Let me know your thoughts!!!!
Posted Mar 27, 2011 5:49 PM ET
Edited Mar 28, 2011 5:51 AM ET
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