Direct Answer
Yes. Modified Bitumen (Mod Bit) and Built-Up Roofing (BUR) can both be designed or upgraded as cool roofs. The main options are reflective mineral-surfaced cap sheets, light-colored aggregate, factory-applied reflective surfacing, and compatible reflective roof coatings. The U.S. Department of Energy specifically identifies reflective aggregate, white mineral granules, factory-applied coatings, and liquid reflective coatings as cool-roof options for BUR and Modified Bitumen systems.
For Florida commercial buildings, this can be particularly useful because cool roofs are designed to reflect more solar energy and release absorbed heat, reducing roof temperatures and potentially reducing cooling demand. ENERGY STAR notes that cool roofs work especially well in hot, sunny climates.
Who This Applies To
This information is useful for:
- Commercial property owners
- Property and facility managers
- Building owners considering roof restoration
- Owners replacing an aging Mod Bit or BUR roof
- Developers planning low-slope commercial roofing
- Owners looking to reduce rooftop heat and cooling loads
Not for: Assuming that every white coating or light-colored roof automatically qualifies as a code-compliant or certified cool roof. The actual product, solar reflectance, thermal emittance, assembly, substrate compatibility, and applicable code requirements must be verified.
1. What Makes a Mod Bit or BUR Roof a Cool Roof?
A cool roof primarily uses a surface with higher solar reflectance and appropriate thermal emittance. Solar reflectance describes how much sunlight the surface reflects, while thermal emittance describes how efficiently the roof releases absorbed heat. ENERGY STAR identifies both properties as important characteristics of cool-roof performance.
Traditional asphalt-based roofs often have dark surfaces that absorb substantial solar energy. Changing the exposed surface to a reflective finish can significantly alter the roof’s thermal performance.
2. Cool Roof Options for Modified Bitumen
Modified Bitumen offers several practical cool-roof configurations.
White or Light-Colored Granulated Cap Sheets
For a new Mod Bit installation, a manufacturer-produced reflective cap sheet with light or white mineral granules is one of the simplest approaches. The reflective surface is incorporated into the roofing assembly rather than being added later as a field coating.
This can provide both solar reflectivity and surface protection while maintaining the multi-ply characteristics of the roofing system.
Factory-Applied Reflective Surfacing
Some modified bitumen membranes are manufactured with reflective surfacing or coatings. The U.S. Department of Energy identifies factory-applied reflective coatings and cool mineral surfaces as options for modified bitumen sheet membranes.
Reflective Roof Coatings
An existing smooth-surface Mod Bit roof may sometimes be restored with a compatible reflective coating. Depending on the specific roof and manufacturer requirements, acrylic, silicone, polyurethane, or other approved coating technologies may be considered.
However, the existing membrane needs to be evaluated first. A coating should not be used to conceal widespread moisture damage, failed seams, severe deterioration, or structural problems.
3. Cool Roof Options for BUR
BUR also has several cool-roof strategies.
Light-Colored Aggregate
Traditional BUR can use aggregate as its exposed protective surface. The Department of Energy identifies light-colored aggregate, including reflective mineral materials, as one method of increasing the roof’s reflectivity.
White Mineral Cap Sheets
A BUR assembly can incorporate a mineral-surfaced cap sheet with reflective white granules. This provides a more reflective exposed surface than a conventional dark surfacing.
Reflective Coatings
Smooth-surfaced BUR may be a candidate for a compatible reflective coating. However, gravel-surfaced BUR can require significantly more preparation because loose aggregate can interfere with coating adhesion.
The DOE specifically notes that modifying existing BUR surfaces for cool-roof performance can require removal or treatment of non-embedded aggregate, and that this work can have implications for the existing roof’s fire rating.
4. Can You Turn an Existing Mod Bit or BUR Roof Into a Cool Roof?
Often, yes—but only when the existing roof is a suitable candidate.
A commercial roofing contractor should evaluate:
- Membrane condition
- Moisture trapped below the roofing system
- Existing leaks
- Blisters or surface deterioration
- Seam and flashing condition
- Existing coatings
- Aggregate attachment and surface cleanliness
- Drainage and ponding water
- Remaining useful life
- Manufacturer compatibility and warranty requirements
If the roof is fundamentally sound, restoration with an appropriate reflective coating may be more practical than replacing the entire assembly. If the underlying roof has widespread moisture or structural deterioration, however, coating it may simply postpone a necessary replacement.
5. What About Gravel-Surfaced BUR?
Gravel-surfaced BUR requires special consideration.
The aggregate provides protection to the underlying asphalt, but it can make direct coating application more difficult. Loose gravel may need to be removed, consolidated, or otherwise prepared before a coating can properly bond.
This is why a gravel-surfaced BUR roof should not automatically be treated like a smooth Mod Bit membrane when evaluating a cool-roof coating.
6. What Are the Benefits in Florida?
Florida’s hot and sunny climate makes roof reflectivity particularly relevant. ENERGY STAR states that cool roofs generally provide greater energy benefits in hot, sunny climates because they reduce the amount of solar heat absorbed by the building.
Potential benefits include:
- Lower roof surface temperatures
- Reduced heat transfer into conditioned spaces
- Potentially lower cooling demand
- Reduced UV exposure of asphalt-based roofing surfaces
- Improved thermal performance
- Potential extension of the useful life of a sound roof
Florida’s current code resources should also be checked for the applicable project requirements. The Florida Building Commission identifies reflectance and emittance requirements for certain low-slope roofs directly above cooled, conditioned spaces, and its 2026 code resources show that the Florida Building Code is being updated.
7. What Should You Check Before Choosing a Cool Roof System?
Do not select a cool roof based only on the color of the surface.
Compare:
- Solar reflectance — how much solar energy the surface reflects.
- Thermal emittance — how efficiently the surface releases absorbed heat.
- SRI where applicable — a useful combined measure of thermal performance.
- Roof compatibility — whether the coating or surfacing is approved for Mod Bit or BUR.
- Existing roof condition — particularly moisture and membrane integrity.
- Warranty requirements — confirm that the proposed treatment is compatible with the roof warranty.
- Fire and code requirements — especially when modifying an existing BUR assembly.
- Maintenance requirements — reflective surfaces can lose performance as they become dirty or weathered.
For products marketed specifically as cool roofing products, independently measured solar reflectance and thermal emittance data can make comparisons more meaningful. ENERGY STAR and the Cool Roof Rating Council are commonly referenced resources for evaluating cool-roof performance.
8. Which Is Better: Cool Mod Bit or Cool BUR?
Neither is automatically better for every commercial building.
| Consideration | Modified Bitumen | BUR |
|---|---|---|
| Reflective cap sheet | Common option | Available in suitable assemblies |
| Reflective coating | Often possible when compatible | Possible, but surface preparation may be more difficult |
| Light-colored aggregate | Possible depending on assembly | Common cool-roof approach |
| Existing-roof restoration | Often a practical option when sound | Possible, but condition and surfacing require careful evaluation |
| Best selection factor | Existing roof condition, compatibility, reflectivity, drainage, warranty, code, and lifecycle cost | |
Bottom Line
Yes, both Modified Bitumen and BUR can be cool roofs. New systems can use reflective mineral cap sheets, factory-applied reflective surfacing, or light-colored aggregate. Existing systems may sometimes be upgraded with a compatible reflective coating after the roof is inspected and properly prepared.
For a Florida commercial building, the best solution is not simply the whitest roof. The right approach balances solar reflectance, thermal emittance, roof condition, drainage, durability, warranty requirements, code compliance, and lifecycle cost.
Related Questions
- What is the main difference between Modified Bitumen and BUR roofing?
- How long do Modified Bitumen and BUR roofs typically last?
- Can a roof coating be applied to any commercial roof type?
- Can cool roof coatings be applied to any existing roof material?
Sources
- ENERGY STAR — Cool Roofs
- U.S. Department of Energy — Guidelines for Selecting Cool Roofs
- Florida Building Commission — Commercial Energy Conservation Code Changes
- Florida Building Commission — Florida Building Code Resources
Last reviewed: October 2026
Related Resources
Review the existing roof condition, surfacing, drainage, warranty requirements, and applicable Florida energy requirements before selecting a cool-roof restoration or replacement system.
Need Commercial Roofing Help?
ShieldLine Roofing can evaluate an existing Mod Bit or BUR roof and determine whether reflective surfacing, restoration, repair, or replacement is the appropriate approach.
Disclaimer: Cool-roof performance and code requirements vary by product, assembly, building, and project location. A qualified roofing professional should verify compatibility, manufacturer requirements, and applicable Florida code requirements before work begins.
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