Modified bitumen roofing system is a type of membrane roofing (the other two types being synthetic rubber and thermoplastic membrane) commonly used in commercial buildings, but that’s also gaining acceptance in residential application.
Modified bitumen roofing is a modification of asphalt roofing as it uses not only asphalt, but also solvents and rubber modifiers. This allows modified bitumen roofs to be:
- Durable (modified bitumen roofs can last around 15-20 years)
- Easy to install
- Easy to maintain and repair
- Resistant to all kinds of weather, from very hot to very cold
- Flexible
Manufacturing and Installing of Modified Bitumen Roofing
When it comes to installing this type of roofing system, a modified bitumen roof can be installed with asphalt, cold adhesives or via a common torch method.
In its manufacture, plasticizers are substituted by introducing modifiers to regular asphalt during distillation. Next, either fiberglass or polyester fiber mating is added to bitumen to strengthen it. This prolongs the longevity and the strength of the system.
Types of Modified Bitumen Roofing Systems
There are two types of modified bitumen roofing:
- SBS
- APP
SBS, or styrene-butadiene-styrene ensures the membrane is more flexible and also makes sure that it can contract and expand better.
APP, on the other hand, usually lasts longer, but due to SBS’ contracting/expanding properties, SBS is the more popular type of modified bitumen roofing.
What Are Its Advantages over Standard Asphalt Roofing Systems
Modified bitumen (as well as synthetic rubber and thermoplastic membrane) roofing systems hold several distinct advantages over the standard asphalt flat roofing systems.
The most notable is that, with asphalt and gravel application, there is always a high possibility of leaks appearing early on in the roof’s lifespan. This is because it is very difficult to properly seal the roof at all connection points and seems.
In addition, repairing and maintaining asphalt and gravel flat roofs can be a chore since it is not easy to spot the leak.
With modified bitumen, on the other hand, not only is leaking greatly eliminated thanks to the materials being seamless, but the roofing system is also easy to patch as the leaks are much easier to spot than with asphalt roofing systems.
