A gravel-surfaced built-up roof (BUR) can sometimes be restored with a protective coating or covered with a new roofing system instead of being completely removed. However, the decision depends heavily on the existing roof’s condition. A professional evaluation should determine whether the BUR is stable enough to serve as a substrate for a coating or roof recover. In Florida, this assessment is particularly important because reroofing must also satisfy applicable Florida Building Code requirements.
What Is a Gravel-Surfaced BUR?
Built-up roofing consists of multiple layers of roofing felts and bitumen, typically finished with a layer of gravel or other aggregate. The aggregate protects the membrane from weather, ultraviolet exposure and physical damage.
Because the gravel is part of the roof’s protective surfacing, it must be carefully evaluated before applying a coating or installing another roof system.
1. Inspect the Overall Roof Condition
The first step is a comprehensive visual inspection. A roofing professional looks for cracks, splits, blisters, open seams, exposed felts, ponding water, deteriorated flashing and areas where the membrane has lost adhesion.
Water-soaked or severely deteriorated roofing is generally not an adequate base for additional roofing. Florida reroofing provisions require removal of existing roof coverings when deterioration prevents the existing system from serving as a suitable base.
2. Evaluate the Gravel Surfacing
The gravel must be sufficiently embedded and stable. Loose aggregate can interfere with coating adhesion and make it difficult to create a uniform coating thickness.
An evaluation should identify areas where gravel is missing, excessively loose, displaced or poorly embedded. Industry condition-assessment guidance specifically recognizes poorly embedded aggregate as a form of BUR surface deterioration.
Loose gravel may need to be removed or secured as part of the preparation process before a coating or recover system is installed.
3. Check for Moisture and Hidden Damage
Moisture is one of the most important factors in determining whether a gravel-surfaced BUR can be recovered. Moisture trapped beneath the membrane or within insulation can cause continued deterioration, blistering and adhesion problems.
Professional contractors may use moisture surveys, infrared scanning or other diagnostic methods to identify wet insulation and concealed problem areas. Any damaged or saturated sections should be repaired or replaced before proceeding.
4. Examine Blisters, Splits and Membrane Adhesion
Blisters and splits require special attention. A roof with widespread membrane failure is generally a poor candidate for coating or recover.
Florida requirements address existing blisters specifically: where blisters exist, they may need to be cut or scraped open and the remaining materials secured before additional roofing is installed.
The contractor should also determine whether the BUR plies remain adequately bonded and whether localized repairs can restore the roof to a stable condition.
5. Determine Whether Coating Is Appropriate
A coating may be considered when the existing BUR is fundamentally sound but needs additional waterproofing and surface protection. Before coating, the roof generally requires thorough preparation, including removal or stabilization of loose aggregate, cleaning, repairs and treatment of problem areas.
The National Roofing Contractors Association’s 2026 roof-coating guidance emphasizes substrate evaluation, repairs, preparation and appropriate coating selection before application.
Compatibility is also critical. The selected coating must be suitable for the existing BUR surface and compatible with any primers, repair materials and existing roofing components.
6. Determine Whether a Roof Recover Is Allowed
If the BUR is structurally and functionally suitable, a roof recover may be possible. The evaluation should consider the number of existing roof layers, structural capacity, drainage, attachment requirements, moisture conditions and the condition of the existing membrane.
Florida code generally requires removal of existing roof coverings when the existing system is water-soaked or deteriorated, when two or more roof-covering applications already exist, or when other specified conditions prevent the existing roof from being an adequate base.
Final Assessment
A gravel-surfaced BUR should never be coated or recovered simply because it appears intact from the ground. The evaluation should cover membrane condition, gravel adhesion, moisture, blisters, splits, drainage, flashing, structural capacity, existing roof layers and material compatibility.
If the BUR is dry, adequately adhered, repairable and suitable as a substrate, a coating or recover may extend the roof’s service life while reducing tear-off and disposal requirements. If significant moisture, deterioration or membrane failure is present, a complete tear-off and replacement may be the more appropriate solution.
For Florida commercial properties, a professional roof assessment should also verify current Florida Building Code requirements before selecting coating, recover or replacement. The 2026 Florida Existing Building Code is now published, so project-specific requirements should be confirmed before work begins.
Related Questions
- Is a roof recover always cheaper than a full tear-off in Florida?
- How does the fire rating differ between a recover and a new roof?
- Should rooftop ballast gravel be removed in high-wind zones?
- What is the code-required minimum slope for a built-up roof versus a single-ply membrane in Florida?
