What is GRP and why do we use it in roofing?
Glass Reinforced Polymer (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 water harvesting systems
- Flexible and versatile
- Long service life
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.
What is polypropylene and where is it used?
Polypropylene is a thermoplastic polymer – an incredibly versatile plastic that can be used in a variety of settings. The material is made through the polymerisation of propene, or propylene, which is the most commercially versatile thermoplastic polymer.
Polypropylene has good chemical resistance, is tough and durable, is the lowest density of commodity plastics and is resistant to fatigue. It can be moulded and extruded. Its properties suit its use for products as diverse as medical devices to carpets and clothing.
Why is polypropylene ideal for roofing products?
Polypropylene is an excellent roofing material, because of its intrinsic characteristics. It is thermally stabilised, UV-resistant, acid rain-resistant and has a non-reflective surface. UV stability prevents colour fade and brittleness and it is lightweight and flexible.
The material has a high melting point and does not deteriorate in the presence of bacteria. It is also easy to modify the composition of the finished products to best suit their application through the use of special additives, and to add different coloured pigments for consistent appearance; this enables manufacturers like Hambleside Danelaw to supply the appropriate colours to suit the products. Being lightweight and flexible, polypropylene is an ideal material for roofing products.
Uses of polypropylene in pitched roofing
Polypropylene is used across the construction industry for roofing and building products. It is used in roofing sheets and insulation as well as being moulded to form roofing products. It is the material of choice for our Interlocking Dry Verge, tile roof vents, slate roof vents and many other roofing products.
Uses of polypropylene in pitched roofing
Polypropylene is used across the construction industry for roofing and building products. It is used in roofing sheets and insulation as well as being moulded to form roofing products. It is the material of choice for our Interlocking Dry Verge, tile roof vents, slate roof vents and many other roofing products.
