Polymer-modified bitumen sheet membranes
Polymer-modified bitumen or modified bitumen (MB) sheet membranes were developed in Europe in the early 1960s and have been in use in the U.S. since the mid 1970’s. Polymer-altered roof membranes are composed of augmenting materials that function as carriers for the hot polymer-modified bitumen as it’s made into a roll stuff. MB roof system membranes are composed of multiple layers. MB roof systems generally are installed as a two ply system and nearly always are completely stuck.
Two types of modified bitumen roofing membranes, SBS polymer-modified bitumen membranes typically are installed in popular mopping of asphalt (similar to BUR systems) or cold adhesive. Some SBS altered membranes are self-sticking; that’s, they comprise an adhesive backing. Self adhesive membranes join the functionality of proven altered bituminous waterproofing compounds with a self adhesive bituminous layer for ease of program. Changed bituminous roof membranes are a popular choice for low-sloped roofs because of their proven long-term performance. APP polymer-modified bitumen membranes generally are heat-welded or torch-employed. Typically, APP modifiers impart a “plasticized” quality to asphalt, and SBS modifiers impart a “rubberized” quality to asphalt. EPDM and mB membranes, a thermoset membrane, frequently are perplexed by consumers due to colloquialisms. MB and EPDM membranes are sometimes called “rubber roofs.”
NRCA does urge that Modified Bitumin meet the standards established by ASTM International
SBS polymer modified bitumen products.
- ASTM D6162, “Standard Specification for Styrene Butadiene Styrene (SBS) Modified Bituminous Sheet Materials Using a Combination of Polyester and Glass Fiber Reinforcements”
- ASTM D6163, “Standard Specification for Styrene Butadiene Styrene (SBS) Modified Bituminous Sheet Materials Using Glass Fiber Reinforcements”
- ASTM D6164, “Standard Specification for Styrene Butadiene Styrene (SBS) Modified Bituminous Sheet Materials Using Polyester Reinforcements”
- ASTM D6298, “Standard Specification for Fiberglass Reinforced Styrene Butadiene Styrene (SBS) Modified Bitumen Sheets with a Factory Applied Metal Surface”
APP polymer modified bitumen products
- ASTM D6222, “Standard Specification for Atactic Polypropylene (APP) Modified Bituminous Sheet Materials Using Polyester Reinforcements”
- ASTM D6223, “Standard Specification for Atactic Polypropylene (APP) Modified Bituminous Sheet Materials Using a Combination of Polyester and Glass Fiber Reinforcements”
Modified bitumen roofing performs well in exceptionally cold weather. This stuff was designed to stay flexible when the mercury drops below freezing. It’s less likely to break and create flows because it will not become brittle in cold weather.
Modified bitumen roofing is not dark in color and has heat-reflective properties. That means that it won’t retain heat on a bright day, so your AC system won’t need to work hard to keep your building cool. Additionally modified bitumen roofing is recyclable.
The older fashion of modified bitumen roofing calls for warmed setup, which can be a fire hazard, as lots of buildings have parts or wooden constructions on or near their roofs. Luckily, though, this kind of roofing technology has improved. More and more, makers are going toward cold-adhesive, self-adhering modified bitumen.