Q: Do I need to use a housewrap over the polyisocyanurate foam sheathing product?
A: Not if the seams are taped. Be sure the rim joist (band joist) is covered. A housewrap is designed to provide an air barrier. The foam sheathing product will provide this air barrier if the seams are taped and therefore it is not necessary to use a housewrap in conjunction with the foam sheathing. Common leak points such as around windows, doors, penetrations and other areas not covered by the foam sheathing need to be sealed separately