The treatment of metal roofs will vary, depending on the condition of the roof and the environment in which it exists.  If it is factory painted and in good condition with no rust, no primer would be necessary.  If patches of rust are present, these areas should be cleaned and spot primed.  If rusting is extensive and covers large areas, the entire roof should be primed.  If the roof is galvanized, whatever its condition, it should be primed.  The ideal primer would be a moisture-cure urethane primer such as Polaprime 21.  The basecoat and finish coat would be the same material and would vary, depending on roof design and environmental exposure.  Most metal roofs would be coated with a high quality elastomeric acrylic coating such as Polaroof AC.  If the roof is flat or has an extremely low slope, then a solvent-based ethylene elastomer coating such as Polaroof NW would be used.  In an industrial environment, a metallic poly- urethane coating such as Polaroof RAC would be used; and in a severe industrial environment, an oxazolidone polyurethane coating such as Polaroof RAC-OZ would be used.  If a copper or gold finished appearance is required, then a synthetic rubber/resin compound with metal flake dispersion such as RoofdX Copper or RoofdX Gold would be used.  All of these coatings may be reinforced with Roofab polyester fabric to make repairs to the seams, laps, and penetrations.  Fasteners are sealed with a pre-treatment of the same material as is used for the basecoat and repair.

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