Products / Atlas Summit 180 Synthetic Underlayment

Summit 180 is Atlas's woven polypropylene synthetic underlayment with a UV-resistant, anti-skid non-woven top surface, for steep-slope roofs under asphalt shingles, metal, clay and concrete tile, slate and wood. Atlas's page and data sheet describe a 10-square roll of about 30 lbs., performance from -40 to 240 degrees F and UL 790 fire compliance. Atlas's own copy disagrees on exposure: the description and features say 180-day UV exposure while the compliance list reads "AC 207, UV Exposure for 60 Days".