Roll roofing is often installed over bare wood sheathing or sheathing that has been painted with a primer. Applying roofing felt first will better protect the sheathing against condensation, as well as against leaking. If the roof is sloped, you can use the exposed-nail method. For a slightly sloped roof, use the concealed-nail method shown. For a flat or nearly flat roof, use double coverage, although a torch-down modified bitumen or EPDM roof is a better solution. Working with a helper, expect to spend half a day installing flashings and roll roofing for a 700-square-foot roof with modest complications. Prepare the roof by tearing off the old shingles, or by preparing for a reroof. Since this is the least difficult of roofing materials to install, only basic carpentry skills are needed. Then, set the first course in the cement so it overhangs by about ¼ inch. Position and roll out the roofing carefully because it is not easy to reposition, then press it into the cement. Nail only its top edge (the part that is bare of mineral coating). Coat the top edge with a 4- to 6-inch-wide layer of roofing cement and apply the next courses in the same way.
