Helpful advice and information of GRP roof

What is GRP?

A: GRP is an abbreviation for Glass Reinforced Polyester, otherwise known as Fibreglass Roofing or Glass Fibre. GRP materials have been extensively used within the marine and automotive industries for over half a century for use on boat hulls, car bodies and even lightweight aircrafts. This technology has been developed for use on roofing systems and become a highly popular choice for fiberglass chopped strand mat flat roof applications.

What does a GRP roof consist of?

A: A GRP roof consists of several layers. Firstly a base layer of cold applied polyester resin is applied onto new 18mm OSB3 timber decking, the base layer is consolidated and reinforced with a layer of fibreglass matting (typically 450 or 600 g/m2), then an additional layer of resin is applied to form the main waterproofing laminate. The system is made complete with an arrangement of pre-formed GRP edge trims to form drip and water check, flashing details. For the final appearance a coloured topcoat is then applied to the roof and left to cure.

Is GRP roofing cost effective?

A: Yes, when comparing costs on flat roof materials, GRP is surprisingly cost effective. GRP roofing is more expensive than a re-covering using traditional materials, however please bare in mind that a quote for GRP will include for new 18mm OSB3 decking boards as part of the price.

Can I walk on my new GRP roof?

A: Yes, one the inherent properties of GRP fibreglass is a tough, hard wearing surface which is puncture and impact resistant. When used in conjunction with a 600g/m2 reinforcement matting GRP can be used for balcony and walkway applications.

Does a GRP roof have joints?

A: No, GRP roofs are free of joints or seams due to the nature of it's cold applied resin application. Regarding of shape or size a GRP roof is completely seamless.

How long does it take for a GRP roof to cure?

A: GRP resins are mixed with catalysts to enable rapid curing even at low temperatures. Typically a GRP roof will harden with an hour of application depending on site conditions.

Can a GRP roof incorporate new insulation?

A: Yes, a GRP roof can be incorporated into warm or cold roof design. Where an existing felt roof is present a warm roof conversion can be achieved by overlaying new PIR insulation boards over the existing felt roof.