How many coats of paint for a vapor retarder
When the code requires/allows a Class II or III vapor retarder, and we want the wall to “breathe” in both directions, it seems that using a paint or primer with the appropriate perm rating will only work for a while. I assume that the Class III paint, if the wall is repainted every few years (or if we call for 4 coats, f. ex.) may turn it into a Class I vapor barrier. True? If the Class II product is expensive, would additional coats of Class III paint accomplish the same permeance?
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