Modified Bitumen
A proven multi-layer system for flat and low-slope roofs. Modified bitumen combines the reliability of built-up roofing with modern polymer technology for superior flexibility and waterproofing.
Time-Tested Flat Roof Technology
Modified bitumen has been protecting commercial buildings for over 40 years. The technology takes traditional asphalt and modifies it with polymers that dramatically improve flexibility, durability, and UV resistance — critical properties for flat roofs in the High Desert.
Multi-Layer Peace of Mind
Unlike single-ply membranes that rely on one layer, modified bitumen systems use two or more layers of waterproofing membrane. This built-in redundancy means a minor puncture or damage to the surface layer doesn’t result in an immediate leak — giving you time and protection.
Flexibility for Desert Conditions
The High Desert’s extreme temperature swings — from well over 100 degrees in summer to near freezing on winter nights — put enormous stress on flat roof materials. Modified bitumen’s polymer-enhanced flexibility allows it to expand and contract without cracking or splitting.
Practical and Repairable
One of modified bitumen’s biggest advantages for building owners is its repairability. Damaged areas can be patched quickly and effectively without replacing the entire roof. This makes ongoing maintenance cost-effective and minimizes disruption to business operations.
How We Install Modified Bitumen
Assessment & Planning
We evaluate the existing roof system, drainage patterns, and any existing penetrations that need to be addressed.
Base Sheet Installation
A fiberglass-reinforced base sheet is mechanically fastened or self-adhered to the roof deck as the foundation of the system.
Cap Sheet Application
The modified bitumen cap sheet is torch-applied, cold-adhered, or self-adhered depending on building requirements and conditions.
Flashing & Sealing
All transitions, penetrations, and edges receive multi-ply flashing reinforcement for complete waterproofing.
Advantages & Considerations
Advantages
- Excellent waterproofing with multi-layer redundancy
- Flexible — handles building movement and temperature swings
- Can be torch-applied, cold-applied, or self-adhered
- Reflective cap sheets available for energy efficiency
- Easy to repair and maintain
Considerations
- Shorter lifespan than single-ply membranes
- Torch application requires experienced crews and fire precautions
- Granule loss over time reduces reflectivity
What Makes Modified Bitumen Stand Out
SBS Modified Bitumen
Styrene-Butadiene-Styrene polymer modification provides rubber-like flexibility that handles thermal expansion and building movement.
APP Modified Bitumen
Atactic Polypropylene modification provides excellent UV resistance and heat tolerance — ideal for High Desert installations.
Reflective Cap Sheets
Factory-applied white or aluminum reflective surfaces meet cool roof requirements and reduce cooling costs.
Multi-Ply Redundancy
The layered system means even if one layer is compromised, the layers beneath continue to protect against water intrusion.
See Modified Bitumen Up Close
Torch-applied modified bitumen membrane on a commercial building
Multi-layer modified bitumen system with cap sheet
Finished modified bitumen roof with reflective granule surface
Common Questions About Modified Bitumen
What's the difference between SBS and APP modified bitumen?
SBS is more flexible and handles temperature swings better, making it ideal for the desert's hot days and cool nights. APP has superior UV resistance and is typically torch-applied.
Can modified bitumen be installed over an existing roof?
In many cases, yes. A new modified bitumen system can be installed over an existing roof if the deck is in good condition and local codes allow it, saving the cost and waste of a tear-off.
Ready to Talk
About Your Roof?
Fill out the form and we'll get back to you within 24 hours with a free estimate. Or call us directly — we pick up the phone.
(760) 240-0088- Free, no-obligation estimates
- Response within 24 hours
- Licensed, bonded & insured