FOIL Type C Single-Sided Foil Vapor Barrier is engineered to be a core layer in efficient, long-lasting sauna construction. This reflective barrier helps raise your sauna’s effective R-value by sending radiant heat back into the room instead of letting it dissipate into wall cavities. At 3.28' x 82.02' (269 sq. ft.), one roll provides generous coverage for saunas up to approximately 6' x 8' x 7', reducing waste and simplifying planning. Installed over insulation and stapled directly to the studs, it creates a continuous shield that limits moisture migration, helping protect framing, insulation, and exterior finishes from damage. When seams are overlapped and sealed with compatible tape, FOIL Type C Single-Sided Foil Vapor Barrier supports a tight, efficient envelope that pairs perfectly with tongue and groove interior paneling and modern electric or wood-burning sauna heaters.