Manufactured by Boral Roofing, Boral® Ply 40 is an SBS modified fiberglass reinforced underlayment/base sheet for tile, shingle, or shake roofing. Easily installed and ideal for use with metal roofing systems, Boral Ply 40’s modified asphalt minimizes the wrinkling and buckling which is commonly associated with non-modified membranes. An all-season solution, Boral Ply 40 offers durability and better protection than felt at a low cost.
The recently improved underlayment now offers an uncovered exposure time, without any degradation, of six months, which is an improvement from its original three-month uncovered exposure time. Boral Ply 40 is available in 216 sq.ft. rolls, each weighing 80 lbs. Certifications and approvals include: ASTM-D6757, D4601, ASTM-D226, and D4869.