Roof coatings can improve the weather resistance, reflectivity, and service life of a commercial roofing system, but a common question is whether a coating automatically has its own fire rating. Generally, no. A roof coating should not be assumed to carry an independent Class A, Class B, or Class C roof fire classification simply because the coating itself is marketed as fire-resistant. Fire performance is usually evaluated as part of the complete roof assembly and its tested installation.
How Roof Fire Ratings Work
Roof fire classifications are commonly established through testing such as ASTM E108 or UL 790. These tests evaluate how a roof system responds to external fire exposure, including flame spread and related fire behavior. Florida Building Code provisions reference ASTM E108 for roof fire classification.
This distinction is important because a roof is not simply the coating on top. The complete assembly may include the roof deck, insulation, existing membrane, adhesive, cover board, primer, and coating. Florida code materials define a roof assembly as incorporating multiple components, rather than treating the top coating as the entire fire-rated system.
Recent Florida code-development material makes this point even more clearly: ASTM E108 and UL 790 fire tests evaluate a roof assembly, which can include the roof covering and other components installed over the roof deck.
Can a Roof Coating Be Part of a Fire-Rated System?
Yes. A roof coating can be included in a tested and approved roofing assembly that achieves a particular fire classification. However, the rating may depend on the exact combination of materials and installation conditions.
For example, changing the underlying membrane, insulation, substrate, coating thickness, or other components can potentially change the fire performance of the assembly. Florida’s roofing approval requirements emphasize that approved roof system assemblies must be installed according to their approved requirements and that component substitutions can affect the approval.
Therefore, a contractor should not take a Class A rating from one roof assembly and automatically apply it to another roof simply because the same coating is being used.
What Should Commercial Property Owners Ask For?
When evaluating a roof coating project in Florida, ask the roofing contractor for documentation showing:
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The coating manufacturer’s technical data and fire-performance information
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The tested roof assembly or system in which the coating is approved
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The applicable ASTM E108 or UL 790 test information
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The required substrate and existing roof type
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Required coating thickness and application rate
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Primer, base coat, or reinforcement requirements
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Installation limitations and approved details
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Any applicable Florida Product Approval or evaluation documentation
This documentation is particularly important when a building has specific fire-classification requirements.
Does “Fire Resistant” Mean “Class A”?
Not necessarily. “Fire resistant,” “fire retardant,” and “Class A” are not interchangeable claims. A product may have certain fire-related characteristics without providing a Class A roof classification for every roof assembly.
Class A is a specific roof fire classification supported by the applicable testing and assembly configuration. Florida code provisions, for example, identify Class A, B, and C roof assemblies and reference ASTM E108 or UL 790 for the required testing.
The Bottom Line
Roof coatings do not automatically carry their own independent roof fire rating. The relevant fire classification generally belongs to the tested roof assembly in which the coating is used. A coating may contribute to a Class A assembly, but that classification should be verified for the specific roof system, substrate, materials, thickness, and installation method.
For commercial properties in Florida, Shieldline Roofing can help evaluate whether a roof coating or restoration system is appropriate for the existing roof and applicable code requirements. Before specifying a coating, request the manufacturer’s current technical documentation and verify that the proposed assembly matches the tested and approved configuration.
Commercial Skylights & Roof Access
Related Questions
- How does the fire rating differ between a recover and a new roof?
- Which insulation types affect the fire rating of the assembly?
- What are impact resistance ratings and how are they tested?
- Are impact-rated skylights required in the HVHZ?
- What is the difference between a “roof assembly” and a “roof covering” in code language?
- What VOC regulations apply to roof coatings in Florida?
