Labels:sky | trade name OCR: Double Sheathing Option... Gypsum ci" Adding foam sheathing on top of the gypsum still gives you good solid substrate for the air and moisture borrier However you can choose to use XPS alone in sufficient thickness to act as both an air and moisture barrier. If done this way you should seal the joints just the foam sheathing over the steel studs and accomp lish air and moisture protection directly through the use of the foam sheathing. Those types systems are available also. 5o you can choose to use double sheathing or single sheathing, but remember that typically single gypsum sheathing alone doesn't provide the thermal per formance necessary for energy code compliance ir most par the country Slide #16 AIA Continuing Education Steel Stud Moisture Resistance XpS parts
