Spray-up

An open-mould process in which layers of dry reinforcement are placed in the mould by hand and wetted out with liquid resin using brushes and rollers before curing, usually at ambient temperature. It is the simplest and most widely used method of producing GRP laminates, including site-applied GRP roofing.

A non woven glass reinforcement made from chopped strands distributed randomly and held with a powder or emulsion binder that dissolves in styrene based resins. It gives roughly equal in plane properties in all directions, wets out readily by hand lay up and is the standard reinforcement in GRP flat roofing laminates. It is specified by areal weight.

A pigmented, resin-rich surface coat applied to the mould face before laminating, which cures to form the smooth, weather-resistant outer surface of a GRP moulding. It protects the underlying laminate from moisture and UV exposure and provides the colour and gloss of the finished part.

Fibre drawn from molten glass, the most widely used reinforcement for polymer composites. Different formulations, such as E-glass, E-CR glass, S-glass and AR glass, balance cost, strength, electrical performance and chemical resistance. It is the standard reinforcement in GRP laminates, including liquid applied GRP flat roofing systems.