Double stud wall — mid-wall insulation = EPS or mineral wool?
I plan on a double stud wall with both walls framed 24″ OC and aligned, and OSB sheathing on the outer face of the inner wall as the primary air barrier.
For essentially identical material cost I can use either mineral wool bats or EPS in the mid-wall cavity. The construction sequence would be slightly different as the EPS would be installed on the inside of the outer wall before the inner wall was erected while the mineral wool would be installed after the inner wall was up, through the openings in the outer wall.
The mineral wool offers a slight advantage in advertised R-value but it seems more labor to install would be needed. The EPS being in larger sheets and an effective air stop would seem to be an air sealing benefit.
Am I missing anything? What would you do?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part