Making the most of mod bit – Part 1

By Mule-Hide Products. 

Understanding the two types of cap sheet commonly available.  

Modified bitumen roofing systems are a powerful option in the low-slope roofing world. With over four decades of proven performance, they offer a durable, low-maintenance and budget-friendly option. Modified bitumen (mod bit) not only handles anything that Mother Nature throws at it but also looks good doing it. And there are plenty of membrane and attachment options, meaning they can work on virtually any rooftop! So, how do you know if you are choosing the right combination for your mod bit roof? In this first part of a three-part series, the experts at Mule-Hide Products will cover two types of mod bit cap sheets and the differences between them. 

In general, there are two types of mod bit membrane – SBS and APP. Both are asphalt-based, and in both cases the asphalt is modified with a polymer and reinforced with one or more layers of fabric to create a roofing system that is exceedingly tough and weather-resistant. The polymer used is different, however, making each membrane type better suited to certain environments. 

In SBS membranes, the asphalt is modified with styrene butadiene styrene. They have greater elongation and remain flexible in cold temperatures, helping prevent cracks that can result in leaks. This makes them the right choice for buildings in northern climates where average winter temperatures are lower. 

In APP membranes, the asphalt is modified with atactic polypropylene. They have a higher softening point, giving them superior weatherability, puncture resistance, and ability to withstand foot traffic scuffing at elevated temperatures. As a result, APP membranes are the better option for buildings in southern climates where average summer temperatures are much higher.  

The next question to ask is how the membrane will be attached. Stay tuned for the second part of this series to learn more about the advantages of self-adhering and torch-applied systems. You can also learn more about Mule-Hide Products modified bitumen systems here. 

Original article source: Mule-hide Products