 It is sold in rolls of various widths, lengths, and thicknesses – rolls, long and "15 lb" () and "30 lb" () weights are common in the U.S. – often marked with chalk lines at certain intervals to aid in laying it out straight on roofs with the proper overlap (more overlap for flatter roofs).It can be installed in several ways, such as staples or roofing nails, but it is also sometimes applied in several layers with hot asphalt, cold asphalt (adhesive), or non-asphaltic adhesives.Older construction sometimes used a lighter-weight tar paper, stapled up with some overlap, as a water- and wind-proofing material on walls, but modern carpenters more often uses widths of housewrap.