Proper torching procedure involves passing the torch flame in an “L” pattern across the coiled portion of the roll and up the sidelap area. As subsequent rolls are installed, heat is applied both to the roll and the exposed laps of the membrane being overlapped onto. As it is heated, the roll becomes shiny and the polyethylene film melts away. Adequate heat is confirmed when a uniform flow of melted bitumen compound flows evenly in a 1/4" –1/2" uniform bead that oozes from the applied membrane’s edges. Be sure to heat the entire roll evenly, not just the lap areas, with extra concentration at the laps. Once at the end of the roll, re-roll the untorched half, pulling back to beyond the starting point as much as possible, and repeat the torching procedure.
Proper torching, in an “L” pattern, assures uniform 1/4" –1/2" compound and flow at laps and adequate heat across the coil
Trim the lower outside corner of the roll at an angle as shown. Overlap subsequent rolls 3" at sidelaps (or as specified, min. 3") and 6" at endlaps. Sidelap lines are generally indicated for the applicators’ convenience.