All You Need to Know About Modified Bitumen Roofing

By Evelyn Witterholt. 

In our latest Lunch & Learn, you’ll learn everything about modified bitumen roofing, from its history to its uses to its proper applications. 

Modified bitumen roofing is one of the most popular types of roofing materials for low slope or flat roofs. But if your roofing company is just beginning to offer this type of roof or if you have some new crew members who are eager to learn, we have a webinar for you! In our latest Lunch & Learn, we speak with Jacob Heaps, a product manager from Johns Manville, all about this popular commercial roofing material.  

Jacob begins by telling us the history of modified bitumen roofing, which dates back to the 1960s. These modified types of roofs were an evolution from the original built-up roofing (BUR) and were typically combined with a kind of coating.  

“Using polymer modification, you were able to tweak the physical properties of the asphalt a little bit more, which made it a lot more useful,” he says. “Rather than relying a hundred percent on the installer to put the roof down, manufacturers are now able to control the thickness of the product, which makes it a little bit easier in the field to install.” 

There are two types of modified bitumen roofing: atactic polypropylene (APP) and styrene butadiene styrene (SBS). Jacob explains that they are both modified, but the modifier used in them is what makes them different. APP is modified with a plastic type of polymer and SBS is modified with an elastomeric polymer, and both are reinforced with either glass fiber or polyester. 

“If you're going with something like a glass fiber reinforcement, you'll have really good tensile strength. If you have go with something like a polyester reinforcement, you’ll have a lot more elongation recovery,” he says. 

Check out the entire webinar to learn more about modified bitumen roofing.