Substrate

The structural layer of a flat or low-pitched roof that supports the waterproofing build-up and imposed loads, commonly profiled steel, timber boarding, plywood, oriented strand board, or in-situ or precast concrete. The deck type influences fixing methods, falls, deflection and condensation behaviour.

A preparatory coating applied to a substrate before an adhesive, sealant, coating or waterproofing membrane, improving adhesion by sealing porosity, binding dust or providing a chemically compatible surface. Primer selection depends on both the substrate and the product to be applied over it.

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.