Q: When sealing end laps on a self-adhering modified bitumen roofing system, can you use adhesive or is heat welding required?
A: Yes, you can use adhesive. Mule-Hide #421 Mod Bit Flashing Adhesive – Trowel Grade is a cold-applied bonding agent created for use in installing modified bitumen roofing systems, including self-adhering membranes. Its thick consistency makes it ideal for mating granulated and self-adhering surfaces, creating a bond that sets quickly and becomes stronger during the curing process.
Better yet, Mule-Hide SA-SBS Cap Sheets and SA-APP Cap Sheets feature patented, granule-free FASTLap® engineering for stronger, more reliable end laps. As long as you’re matching sheets at the edges, no adhesive or heat welding is required. If you need to cut a roll, thereby removing the FASTLap, you must create a flat surface for the end lap so moisture won’t sneak in; either heat the surface and embed the softened granules or fill in the nooks and crannies with adhesive.
Whether by using adhesive or FASTLap, you can seal most end laps in self-adhering mod bit roofing systems without firing up the heat welder.