Glass Reinforced Polyester (GRP)

What is GRP and why do we use it in roofing?

Glass Reinforced Polyester (GRP) is, as the name suggests, a polyester material reinforced with the addition of glass fibre (also commonly known as fibreglass). The material is produced by combining thermosetting polyester resin and glass fibres under strictly controlled factory conditions. Glass fibres are applied into the resin with each layer of fibres facing in different directions, enabling the stiffness and strength of the finished material to be controlled. The effect is a strong, lightweight material that is naturally watertight.

The history of GRP

The Egyptians used glass fibre reinforcement in the fabric of clay jars to stop them breaking during transit, but it wasn’t until the 1930s that GRP as we know it today was discovered.

Mass production was accidentally discovered (in 1932) when a researcher directed a jet of compressed air at a stream of molten glass, and produced fibres; four years later, a suitable resin for combining the fibres with plastic as developed.

WW2 saw the material be used widely in aircraft, due to its transparency to microwaves, and in minesweepers as it leaves no magnetic footprint.

Its characteristics have led to its use in boats, sports cars, MRI scanners, PCBs, and a raft of building components.

Reasons why you should use GRP roofing products

  • Lightweight and easy to handle
  • Strong and durable
  • Suitable for use in grey water systems
  • Aesthetically pleasing
  • Exceptional detailing capabilities
  • Flexible and versatile
  • Long service life
  • Fire retardant
  • UV resistant
  • Easy to repair
  • Recyclable at end of service life (as long as provided by responsible manufacturer)
GRP Roof Flashings
GRP Roof Flashings
GRP Rooflights
GRP Flat Roofing Systems
GRP Living Flat Roofing System

Environmental benefits of GRP

  • In terms of embodied energy, GRP performs far better than alternative plastic roofing materials: a rating of 6 CO2/Kg against PVC’s 16, and bitumen’s 43
  • GRP is safe to use in grey water systems and does not emit any chemicals once installed.
  • GRP roofing can, in membrane form, be used to create a green (living) roof, without any need for a separate root barrier.
  • As part of a warm roof construction, it can help achieve U values in line with Green Deal requirements.
  • At the end of its long service life, GRP can be broken down into its component materials, which can then be recycled into new materials, additionally saving the customer money and reducing impact on the environment.

Risk of theft

Theft of lead and other metals from roofs continues to be an issue. GRP makes for an ideal alternative, dependent on the application, and can be formed to replicate the appearance. GRP also has no scrap value and no value to the thief.

GRP manufacture at Hambleside Danelaw

Hambleside Danelaw has been producing quality roofing products in the UK for over 40 years. We pride ourselves on producing durable and user friendly products that offer long term roofing solutions. Our GRP products are manufactured in our state of the art factories, here in the UK, located in Daventry. As a reliable manufacturer, we also offer excellent customer support after the project has finished, and an insurance backed guarantee for peace of mind.

For a healthy roof, use GRP, a durable, versatile, lead alternative material.

Why not take a look at our Dryseal GRP flat roof system and our GRP flashings range for pitched roofing?