Floor insulation, Roxul vs closed foam
The foundation of my house (1152 sq/ft) is post and pier and there is no perimeter enclosure.
The bottom of the 2×8 floor joists are about 40″ from the ground.
I am considering two methods of insulation.
The first method is 7.25″ thick Roxul batts (R30) that are covered with 7/16″ OSB sheets.
The second method is 1.5″ (R10) of sprayed closed cell foam.
The cost to me of both methods (if I don’t count my labor with the Roxul) is nearly identical, about $2000.
The Roxul has the advantage of about 3x the R value of the foam.
However, the Roxul has a couple of big disadvantages as well.
I would be doing all the labor with the Roxul method and since the floor joists are on 19.2″ centers, it would require quite a bit of cutting the batts, since Roxul doesn’t come in that width.
A big advantage of the closed cell foam is that I would not be doing any of the labor. Also, it appears that the foam would seal better against air infiltration.
The only apparent disadvantage of the foam is the lesser R value, however, I’m not sure that I really need more than R10 in the floor (The location is in western Arkansas).
I kind of leaning toward the foam (thinking about the labor with the Roxul, I’m 68).
What say ye ?