The foam insulation board in covered with GreenGuard RainDrop house wrap. This is a robust building paper that has built in micro drainage channels to provide a passage for any water that might get behind it to migrate down and out.  

Finishing the exterior system continues with placement of the 2” of XPS foam on the exposed exterior walls. This insulation is installed outside the Perm-A-Barrier membrane and will (theoretically) prevent moisture condensation inside the wall cavity as it moves the “dew point” outside the wall. It will be wrapped with “Green Guard” building paper, mainly to protect the foam from UV degradation.  Vertical 1x4 battens of composite wood, Hardy Trim, will go on top of that to mount the clips for the interchangeable metal shingle rain-screen system.