Complete Guide to a Modified Bitumen Roof

Designed for flat or low slope roof structures built-up roof (BUR) membranes have been in use for over 100 years. Commonly referred to as “tar and gravel” roofs. BUR systems are made up of alternating sheets of fabric and bitumen to create a finished membrane. The number of plies or layers used in the roof determines how many plies are in the cross-section.

Complete Guide to a Modified Bitumen Roof

What Is A Modified Bitumen Roof?

Modified bitumen roofs first appeared in Europe in the 1960s. They made it across the pond and successfully used it in Canada and the United States by 1975. Modified bitumen (MB) roofing systems are a close relative of the hundreds of years old BUR roofing systems. Asphalt-based and designed for flat or low slope roof structures make MB roofs similar to BURs. However, modified bitumen roofing systems give designers and installers a greater variety of options when compared to BUR.

An array of methods apply modified bitumen roofs. These can be “cold-process” adhesives, the torch-application method, or “hot-mopped” like BUR. In addition, the self-adhering sheet is the latest in MB innovations. This method uses modified MB sheets with a combination of special polymers applied to it. Manufactured with release paper that the installer removes while rolling it out. It then sticks itself to the substrate removing the hazards associated with VOC (volatile organic chemicals), hot asphalt, and torches.

Advantages of a Modified Bitumen Roof

MB roofs have many advantages associated with them. For one it is very long-lasting, easily surviving for 20 years or more. Furthermore, they have a very long and substantial history of performance. Unlike some more modern methods of roofing that cannot be counted on to hold up over time. MB roofing systems can be seamless, unlike other methods that have open seams covered by another material. These materials can weaken over time, causing leaks and irreparable damage. However, an MB roofing system no matter the application method the seams are melted together. This helps to stop leaks and prevents future damage.

MB roofing systems also have high tensile strength and are very durable. They are far less likely to crack in ways that other flat and low slope roofing systems are known for. MB roofs are rated for hail, fire, and wind, which makes them less likely to be damaged in these events. In addition, they are much more durable to high foot traffic. Also, it is easy to maintain when it needs maintenance or repairs. Another advantage is that they have great thermal performance and insulated systems achieve high thermal value. This can mean great savings on your next energy bill. The cherry on top is that MB roofs usually include a very long manufacturer’s warranty. This can give you peace of mind over your investment.

Disadvantages of a Modified Bitumen Roof

Despite having many advantages MB roofing systems like all roofing systems do present some drawbacks. The first has to do with their black color which absorbs various forms of heat instead of reflecting it. The building can become superheated below if insulation is not properly used. However, the UV rays and heat will not damage the material itself. 1-ply MB roofing can break down too early as it is not as durable as 2-ply or 3-ply. While 2-ply or 3-ply is more desirable it can be significantly more expensive to install. This makes it one of the more pricey flat and low slope roofing products around.

If your roof is more prone to puddles and standing water, it can age the MB roof prematurely. This can speed up damage caused to the roof by rain, snowstorms, and other weather events. Finally, not all MB roofs contain granules in the installation procedure. The Installation has to include Granules to help further protect the roof from the sun. However, if not included, it could lead to higher temperatures that can eventually lead to roof damage.

Call The Professionals

If you have any questions about modified bitumen roofs and how they can help you call us. We are always here to help our customers find the right product to fit their budget and needs. Our highly trained crew is here to guide you throughout the process. Call us for a quote today!