Modified Bitumen Roofing in Chicago, IL
Modified bitumen, often called "mod bit," is a rugged multi-layer system that has protected flat roofs in the Chicago area for decades. It is a strong option for buildings that see foot traffic, rooftop equipment service, or harsh seasonal swings. All Available Roofing installs and repairs modified bitumen systems for commercial and industrial clients.
What Is Modified Bitumen?
Modified bitumen is an asphalt-based roofing membrane reinforced with polymer modifiers, which give it flexibility and strength. It is installed in one or more plies and can be applied several ways: torch-applied, hot-mopped, cold-applied with adhesive, or self-adhered. The top layer is often a granulated cap sheet that protects against sun and weather.
SBS vs. APP
The two main polymer types behave differently:
- SBS (styrene-butadiene-styrene) is rubber-like and flexible. It handles temperature swings and building movement well, making it a common choice for cold climates.
- APP (atactic polypropylene) is plastic-like and holds up well against UV exposure, with excellent weather resistance.
We recommend the right one based on your building's roof structure, use, and exposure.
Modified bitumen offers four clear advantages for commercial roofs.
Why Choose Modified Bitumen
Redundancy
Multiple plies mean a single flaw is less likely to cause a leak.
Durability
The thick, reinforced surface resists punctures, foot traffic, and hail better than thinner single-ply membranes.
Repairability
Damaged areas can usually be repaired by patching or re-applying material.
Cold-weather performance
SBS systems stay flexible through Chicago's coldest stretches.
Installation Methods
Some buildings cannot allow open-flame torch application because of fire code, insulation, or tenant concerns. We offer cold-applied and self-adhered options that avoid open flame, and we will explain which method fits your property.
Our Modified Bitumen Services
- New modified bitumen installation
- Tear-off and replacement
- The roof recovers where permitted.
- Leak repair and seam work
- Roof inspections and maintenance programs
Modified Bitumen FAQ
How long does modified bitumen last?
Typically 15 to 25 years with proper installation and maintenance. [Confirm warranty.]
Is modified bitumen safe to install?
Yes, when done by trained crews following safety and fire-code requirements. Torch-free methods are available when needed.
Want a modified bitumen estimate? Call 773-339-9370 or Request an Estimate