Not every covering counts as a thermal barrier for spray foam. In BC, commonly accepted options include ½-inch (12.7 mm) gypsum drywall, 11 mm plywood or OSB with supported joints, sheet metal, concrete or masonry, plaster, and specially tested coatings that meet CAN/ULC-S124 standards. What doesn't count? Paint, poly sheeting, house wrap, and fibreglass batts. Choosing the right spray foam thermal barrier material depends on the room, your budget, and how you plan to finish the space. Our guide includes a simple table to help you compare materials and avoid costly rework. Explore the guide: https://westerninsulation.ca/spray-foam-thermal-barrier-bc/