About Modified Bitumen Roofing
Modified Bitumen (MB) roofing is the latest iteration of Built-Up Roofing (BUR) that has been in use for centuries. BUR is simply a roof system comprised of multiple layers of roof felt saturated with bitumen. These systems have three components; a waterproofing component, reinforcing component, and a surfacing component to protect the others. MB Systems as we know them today developed in the 1960’s with the advent of synthetic polymers added to the asphalt to increase elasticity and resistance to brittleness at cold temperatures. MB Roof Systems can be installed by torch application, hot mopping, or cold process adhesives. Improvements in adhesives and manufacturing processes have made the cold process method preferable due to the elimination of risks such as fire and hazardous fumes.
Cold Process MB systems have a combination of base sheet, ply sheets, and cap sheet. The number of ply sheets. The addition of one of more ply sheets increases the life expectancy and warranty associated with the roof system. The cap sheet is typically mineral or gravel surfaced which allows for many color options including “cool roof” coatings to maximize energy efficiency and achieve energy star ratings. As with most roof systems, there are many considerations such as desired lifespan, wind uplift ratings, compatibility with chemicals