Products / Malarkey 406 Secure Start HT

Secure Start HT (SKU 406) is Malarkey's self-adhering high-temperature underlayment with a textured polypropylene surface over an asphalt-based adhesive, built in five layers with a 3 in. selvage, recommended for full-deck coverage under metal roofs and also used under asphalt shingles, wood shakes and mechanically fastened tile and as a flashing membrane. The February 2026 data sheet gives a 36 in. x 67 ft. roll (201 sq. ft.), 48 mils nominal and 50 lbs., thermal stability to 250 degrees F, up to six months of exposure, a Class A fire rating when installed with a fire-rated roof covering, and a limited lifetime warranty in combination with Malarkey limited-lifetime shingles and accessories.