Commercial Flat Roofing Systems: A Comprehensive Guide

Not all commercial flat roofing systems are created equal. The roof of any commercial building is more than just a protective cover. It’s a critical component that safeguards the infrastructure and its occupants from various environmental elements. Therefore, understanding different commercial flat roofing materials, types & costs is essential to selecting the best roofing system for your commercial building. 

Understanding Commercial Flat Roofing Systems

There are many commercial flat roofing materials, types & costs to consider. The main types include:


  • Built-Up Roofing (BUR): Also known as tar and gravel roofs, these are traditional hot-tar-and-gravel roofs made from three or more layers of waterproof material alternated with hot tar and topped with a layer of smooth river stone. BUR systems are durable and fire-resistant but can be heavy and require substantial joists in the roof structure to support the weight.
  • Modified Bitumen Roofing (MBR): This single-ply rolled roof is similar to ice-and-water shield but imbued with a mineral-based wear surface. Torch-down systems involve heating the adhesive as the material unrolls, but newer peel-and-stick systems are safer and easier.
  • Rubber Membrane (EPDM): EPDM is a true rubber that can resemble an inner tube but is engineered to resist damage from sunlight. It’s lightweight, scuff- and tear-resistant, and relatively easy to install.


Maintenance, Lifespan, and Costs

The lifespan of a flat roofing system depends on the type and material used. BUR systems can last up to 30 years, MBR systems about 20 years, and EPDM roofs can last between 15 to 25 years with proper maintenance.

As for costs, they can vary significantly based on the type of system, material used, size of the roof, and localized roofing market trends and conditions. For example, BUR systems are generally the most expensive due to their durability, while MBR and EPDM systems are often less costly.

Choosing the right commercial flat roofing system depends on various factors like your budget, structural capacity of the building, and specific needs. While BUR systems offer superior durability, they may not be suitable for buildings with weaker structures due to their weight. MBR systems, on the other hand, are a good balance between cost and durability, while EPDM systems are lightweight and easy to install.


Thoroughly consider your building’s needs, consult with a professional roofer, and make an informed decision that balances cost, durability, and maintenance needs.