TPO single-ply
A white, heat-welded membrane that reflects sun and keeps cooling loads down. It is fast to install and widely used on large flat roofs in Florida. Quality depends on membrane thickness, seam welding and a fastening or adhesive system rated for the building's wind zone.
Modified bitumen
Multi-ply asphalt-based systems with a cap sheet, often torch-applied or cold-applied. They are tough and forgiving to foot traffic, and repair well, but they are heavier and usually cost more than single-ply. A reflective coating helps in Florida heat.
Standing-seam metal
Concealed-fastener metal panels give the longest life and excellent wind performance when engineered correctly, and they suit low-slope and sloped roofs with enough pitch. Cost is higher up front; lifespan of 40 years or more can make it cheaper over time.
Ponding and drainage
Standing water shortens the life of any low-slope system. If a roof ponds, solving slope, scuppers and drains is part of the design, not an add-on.
How to choose
Match the system to the building: life-cycle cost, wind exposure, roof traffic, HVAC density, warranty requirements and the owner's plans for the property. We recommend the system after surveying the roof, not before.
General information, not legal or insurance advice. Confirm requirements with your insurer and local building department.