[BigV]

looks like roll roofing. same material as asphalt shingles, but in roll form. I used it for my roofing (there's a thread around here somewhere). It's popular for low pitch rooves. Also, it may be the case that the roofing material, whatever it is (sure looks like some kind of rolled material) has been coated with some kind of sealant. lots of flat or near flat rooves are coated in silvery sealant as protection against water intrusion due to the slower pace of runoff with a lower slope.