Does Rockwool Board Follow The Same Exterior Rigid Insulation % Requirement?
If part of the current building science minimum exterior foam thickness requirements for different wall thicknesses and climates is partially determined by the inability of walls to dry to the outside due to the low permeability of foam, would the percentage that needs to be observed change if the exterior insulation”foam” is rockwool board that has a higher outward drying potential?
I understand that the recommended percentage values are based on increasing the temperature of the sheathing, but from what I’ve read it seems that the percentage is also partially based on the inability of the walls to dry to the exterior due to the exterior foam layer.
Perhaps the prescriptive values are not meant to be taken into account when using exterior rockwool board. Rockwool is not a “foam” afterall. It seems like this could use some clarification since rockwool board is often used interchangeably with exterior rigid foam board.
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