Modified Bitumen Roofing for Commercial Buildings

Modified Bitumen (Mod-Bit) is a rugged, durable roofing solution with over 50 years of success in low-slope roofing. It is a prevalent, tried-and-true roof system for commercial facilities, well-known for unparalleled performance in harsh conditions. Properly installed and maintained Modified Bitumen roofs may last up to 20 years or more.

What is a Modified Bitumen Roof?

Mod-Bit roofs are generally composed of alternating layers of asphalt, synthetic rubber and a reinforcing scrim. Together, these components ensure that your roof is weather and UV-resistant and, of course, watertight. Initially introduced in the 1960s in Europe, Mod-Bit roofs are an evolutionary step from Built-up Roofing (BUR). In Mod-Bit roofs, the bitumen can be modified in two different ways: with plastic (Atactic Polypropylene or APP) or synthetic rubber (Styrene Butadiene Styrene or SBS).

Modified Bitumen Roof Installed in South Carolina
Mod Bit Installation by CentiMark on a resort
Modified Bitumen installation over a factory by CentiMark
Mod Bit Installation


Atactic Polypropylene (APP)

Often referred to as "plastic asphalt" with a serviceability range between 15F and 300F. APP has excellent UV and heat resistance, allowing it to be used for "cool roofs" and in hot climates.

Styrene Butadiene Styrene (SBS)

Referred to as "elastic asphalt" with a serviceability range between -20F and 270F. It is an excellent solution for areas with drastic shifts in temperature.

Benefits of Modified Bitumen Roofing

Outstanding durability

Outstanding durability

Mod-Bit commercial roofs are well-known for being resilient to punctures, tears and hail.


Properly installed and maintained, Mod-Bit commercial roofs inherently provide resistance to water intrusion due to their rugged design. However, the correct installation is critical to prevent roof leaks.


Mod-Bit roofs are great for areas with extreme temperatures because their flexible yet reinforced nature allows them to move with your building as it expands or contracts.
Energy efficiency

Energy efficiency

The top layer of your Mod-Bit roof can be designed to reflect UV and heat minimizing the energy loss of your building.


Depending on your application and needs, each of the layers of your roof installation can be installed to meet your specifications.

Mod-Bit Roofing Installation Process

CentMark offers multiple types of installation, depending upon your custom specifications. For example, the adhesive can be applied hot or cold and, in some cases, mechanical attachment is used. Most Mod-Bit installations require two layers of membrane, however, some applications call for multi-ply installations that include more layers.

Modified Bitumen vs. Built-Up Roof (BUR)

While these roof systems are similar, there are distinct differences between Mod-Bit and its older cousin, Built-Up Roof (BUR). Looking at those features before choosing the right product for your commercial facility is essential.



Mod Bit Installation By CentiMark
Modified Bitumen Red Cap Bright Red Roof
Grey Mod Bit Roof by CentiMark
Modified Bitumen Roof Red Color

The Layer of Gravel in BUR Roofs Provides the Following Benefits Compared to Mod-Bit

  • ✔ Additional fire and hail resistance.
  • ✔ Appealing look for the roof when it's a part of the ambiance. For example, multi-level high rises where the roofs are visible from upper levels.

However, the same gravel layer may obstruct proper drainage of your roof and cause ponding water, a challenge you won’t have with Mod-Bit roofs.

How Much Does a Mod-Bit Roof Cost?

Mod-Bit roofs are economical to install and require regular maintenance to reach their full life expectancy. Mod-Bit is not a seamless application, so it is vital to check on its health regularly.

Why Choose CentiMark as Your Commercial Roofing Contractor?

The workmanship is more important to a sound roof system than the materials themselves. Our mission is to keep our customers' buildings watertight, protect their properties and employees, all in concert with regular business operations. From inspection and installation to repairs and maintenance, we focus on workmanship and attention to detail, providing you peace of mind with our Single Source Warranty that is backed by a multi-million dollar provision. Our dedicated service and production crews attend mandatory safety and installation training regularly. You can rest assured that your projects are OSHA-compliant and completed by experienced, specialized experts every time.

Interested in a Mod-Bit Roof System For Your Commercial Building? Contact Us for Your Free Quote!

Our team of dedicated roofing professionals is just a message away! Let's evaluate your current roof condition, your needs and building functions and discover the most optimal commercial roofing solution for your needs.

* Required information
Contact Us