Modified Bitumin (MODBIT)

Modified Bitumen roofs are single-ply systems that are most often roll-applied to the surface. They are similar to asphalt roofs, but they have additional polymers in their materials that provide added protection from the elements. Mod Bit roofs are installed by first installing a base sheet that separates the roof system from the substrate. The base sheet can either be mechanically attached to the decking or fully bonded to underlying insulation. Once base sheet is installed the rolls are heated with a blow torch, which allows the material to adhere to the roof surface. Manufacturers typically require run-out (or bleed-out) of at least 1/4” to 1/2” along lap seams and end laps to visually assure bonding with blow torch, hot-mopped. Unbonded lap and end seams are common problems found in Mod-Bit membranes. the unbounded lap seams are referred to as “Fishmouths”