Understanding Roof Types Key to Successful Coating Applications
Managers can specify white coatings for use on most roofing membranes and systems. They most commonly are applied to sprayed polyurethane roofs, metal roofs, single-ply rubber roofs, and modified-bitumen roofs. But they can be applied to certain kinds of asphalt built-up roofs.
Prior to specification, managers will need to establish the compatibility between the coating and the underlying roof surface. They can do this by consulting manufacturer recommendations.
Proper Surface Preparation
Primers are useful for improving the adhesion between roof surfaces and coatings and for imparting additional properties to roof coating systems. A compatible primer for a rubber roof coating might provide better adhesion to a rubber roof membrane or improve a coating's permeability rating on a sprayed polyurethane roof.
Most white coatings give a system greater reflectivity and ultraviolet (UV) protection. Managers should consult and follow manufacturer recommendations to ensure workers properly prepare the surface, and they should consider using professional roofing contractors for coating applications. For certain systems, contractors might require special training from the manufacturer in applying the coating. Proper application factors strongly into the subsequent life and performance of the coating.
The roof surface should be clean and dry, and it must have a positive slope to drains. The coating type will greatly dictate the necessary surface condition. Applying white coatings over dirty, wet or contaminated surfaces might produce unsatisfactory results, and acrylic latex coatings are sensitive to dew, rain and other moisture during curing. It is important that workers apply the coating by strictly adhering to the coating manufacturer's recommendations.