Best solution to combine polyurethane and fiberglass batt
I am currently building a house and would like to have 1" of poly sprayed around the perimeter of the house. To save costs and not have poly sprayed the rest of the way on a 2x6 wall, what is the best fiberglass batt to use? Will I loose insulation value if I go to an R-19 and compress the batt into the wall? This would give a R-26 in the wall. Or do I try for 2" of poly and drop down to an r-13 which would give me a R-27. The overall R factors are virtually the same however trying to save cost and get the best insulation combination. Thanks.
My research says Tiger Foam (one inch layer) and fill the remaining space with unbacked fiberglass. I'm going to do a house soon and will do one inch tiger (because it's closed cell and is r7/inch) and r19. This applies to a 2X6 wall anyway.
I'd advocate spraying the entire inside of the exterior walls. If they're there spraying them already, I can't imagine that the cost would be significantly increased. Spray foam yields unusually tight wall construction, and leaving a void in the wall for batt insulation doesn't sound like a good idea to me at all.