Tyvek Protec 160 Roof Underlayment 4' x 50' roll covers 2 Square. the 4' x 50' roll size is more manageable for a one man job, for those smaller projects, or when only a few more square are needed. With its industry-leading walk-ability, it is ideal for slopes 2:12 or higher and can be used under a variety of roofing materials, including asphalt shingles, cedar, metal roof cladding, tile or slate. The four-layer construction offers high performance with a slip resistant coating gripping it to the roof, woven polypropylene giving it strength, a water barrier layer, and grooves on the top layer expelling water and dirt to provide a safer work environment. It is wrinkle-free, easy to chalk, protects the roof during installation as a moisture barrier and withstands UV exposure for up to 6 months. It is trusted protection that can give both professional builders and homeowners greater peace of mind.