Elastomeric coating

Waterproofing formed in situ by applying a liquid resin, typically polyurethane, polymethyl methacrylate (PMMA), unsaturated polyester or a bitumen-based formulation, by roller, brush or spray, which cures to a seamless elastomeric membrane. Often reinforced locally or throughout with a fleece, it is particularly suited to complex details and refurbishment over existing coverings.

Corrosion that develops at the exposed cut edges of pre-coated steel roof sheets, typically at overlaps and eaves, where the steel core is not protected by the factory coating system. It appears as coating delamination and rust creeping back from the edge, and is treated by preparation and application of edge protection coatings before it spreads into the sheet.

The final coat of a coating system, providing the specified colour, gloss and resistance to weathering, ultraviolet light and chemical exposure. It is the system's first line of defence against the environment and largely determines how the finish looks over time.