Yes. Modified bitumen (Mod Bit) and built-up roofing (BUR) systems can both be upgraded into cool roofs using reflective membranes, factory-applied cool surfacing, or specially formulated roof coatings. For commercial buildings in hot climates like Florida, cool roof options can reduce roof surface temperatures, lower cooling costs, improve occupant comfort, and help extend the service life of the roofing system. The key is choosing a solution that is compatible with your existing roof and meets applicable code and manufacturer requirements.
What Is a Cool Roof?
A cool roof is designed to reflect more sunlight and emit more absorbed heat than a conventional dark roof. Two properties determine its performance:
- Solar reflectance – how much sunlight the roof reflects.
- Thermal emittance – how efficiently the roof releases absorbed heat.
A highly reflective roof can stay 50°F to 60°F cooler than a traditional dark roof during sunny weather, reducing heat transfer into the building. (ENERGY STAR)
Cool Roof Options for Modified Bitumen Roofing
Modern modified bitumen roofing offers several cool roof choices.
1. White Granulated Modified Bitumen
Many manufacturers produce factory-made white cap sheets with reflective mineral granules. These provide:
- High solar reflectance
- Long-term UV protection
- No additional coating immediately after installation
- Good compatibility with new roofing systems
This is one of the most common choices for new commercial installations where owners want a durable reflective surface.
2. Reflective Roof Coatings
Existing smooth-surface modified bitumen roofs may be eligible for reflective coatings such as:
- Acrylic coatings
- Silicone coatings
- Polyurethane coatings
- SEBS or SBS-modified coatings
When properly installed over a roof that is still structurally sound, these coatings can restore weather protection while significantly increasing solar reflectance. However, not every modified bitumen roof is a candidate, and surface preparation is critical for proper adhesion. (Roof Coatings Manufacturers Association)
Cool Roof Options for BUR (Built-Up Roofing)
BUR systems also have several reflective options.
Reflective Cap Sheets
Some BUR assemblies use reflective cap sheets designed specifically for cool roof performance.
White Reflective Coatings
Smooth-surfaced BUR roofs can often receive:
- Acrylic coatings
- Silicone coatings
- Elastomeric reflective coatings
These coatings create a bright reflective surface while helping protect the asphalt from UV degradation.
Ballasted or Reflective Aggregate Systems
Certain BUR assemblies use light-colored mineral aggregate that naturally reflects more sunlight than traditional dark surfaces.
The best solution depends on the existing roof condition, drainage, warranty status, and long-term maintenance goals.
Benefits of Cool Roof Systems
For commercial buildings, cool roofs provide multiple advantages:
- Lower rooftop temperatures
- Reduced air conditioning demand
- Improved indoor comfort
- Reduced thermal expansion and contraction
- Better UV protection for asphalt-based roofing
- Potentially longer roof service life
- Lower peak summer energy costs
Florida buildings often benefit significantly because cooling loads remain high for much of the year. (The Department of Energy’s Energy.gov)
Things to Consider Before Applying a Coating
Not every Mod Bit or BUR roof should simply be coated.
A professional roofing inspection should evaluate:
- Moisture trapped beneath the membrane
- Existing leaks
- Membrane adhesion
- Flashing condition
- Drainage performance
- Remaining roof lifespan
Gravel-surfaced BUR roofs, for example, typically require additional preparation before coatings can be installed and may not always be good candidates. (Roof Coatings Manufacturers Association)
Look for Tested Cool Roof Products
When selecting a cool roof system, look for products that have been tested by recognized programs such as the Cool Roof Rating Council (CRRC). CRRC-rated products provide independently measured values for solar reflectance and thermal emittance, making it easier to compare roofing materials objectively. ENERGY STAR also recognizes qualifying cool roof products for many low-slope commercial applications. (Cool Roof Rating Council)
Shieldline Roofing’s Expert Opinion
Yes—both Modified Bitumen and BUR can be designed as cool roofs. At Shieldline Roofing, we look for reflective mineral-surfaced cap sheets, light-colored aggregate, or compatible reflective coatings when specifying these systems for Florida buildings, while also considering durability, drainage, and the existing roof assembly.
Our Key Insights
The U.S. Department of Energy identifies white mineral granules, reflective coatings, and light-colored aggregate as cool-roof options for BUR and Modified Bitumen systems. In hot climates, the benefit can be significant: DOE notes that cool roofs can stay up to 60°F cooler than traditional black roofs during summer conditions.
The Bottom Line
Yes—both modified bitumen and built-up roofing systems have excellent cool roof options. New installations can incorporate reflective cap sheets or factory-produced cool roofing products, while many existing roofs can be upgraded with compatible reflective coatings when the roof is still in good condition.
For commercial property owners in Florida, a properly designed cool roof can improve energy efficiency, reduce rooftop temperatures, protect asphalt-based roofing materials from UV exposure, and extend the overall life of the roof. Before choosing a coating or replacement system, have an experienced commercial roofing contractor inspect the roof to determine the most effective and warranty-compatible solution for your building. Learn More
