Glass Reinforced Polyester (GRP) Roofing

GRP (Glass Reinforced Polyester), originally discovered in 1940’s, has rapidly evolved from originally being used in boat building to becoming the essential material in water tanks, roof lights and waterproof coatings. A combination of corrosive-proof properties together with outstanding aesthetic properties and an unquestionable strength, has granted GRP a world-wide success, so much so that this material is now widely used in the roofing industry.

In its simplest form, a GRP roof is a GRP laminate applied over a high-quality OSB3 deck.  It can withstand practically any weather conditions, has no joins or seams and can be fully adjusted to suit one’s needs both in terms of the design and complexity. That said, it comes in many different colours and can easily blend with any exterior. Additionally, it is flexible and malleable and can be used on any type of flat roof including garages, parapet walls and dormer roofs as well as balconies, roof gardens and roof terraces where epdm alone is not enough. Similarly, a GRP roof is safe and easy to apply, meaning that it does not require the use of heat like old-fashioned roofs. Most importantly, it fits all buildings equally as well, regardless of their size and style.

Every GRP roof consists of four layers, namely:

  1. Ply deck & glassfibre bandage
  2. Glassfibre layer
  3. Top coat
  4. Non-slip aggregate (optional)
GRP Roofing Mechanism via andersonroofing.co.uk

GRP Roofing Mechanism

 In order to apply the roof, it must be laid onto a dry deck and ideally in temperature that does not go under 5°C. The top coat should specifically be in accordance to the GRP roofing style. 

GRP Roofing Example

GRP Roofing Example

GRP roofing application

GRP roofing application

The application process itself consists of:

  1. Preparing the deck
  2. Laying the deck
  3. Edge trims
  4. Laminating (including laying the main laminate)
  5. Topcoating the roof

While the deck preparation is relatively straightforward, the process of laying the deck is slightly more complex and illustrated in the image bellow.

The process of laying the deck,

The process of laying the deck,

Once the deck has ben laid and the edge trimmed, the lamination process begins:

The process of laminating,

The process of laminating,

Finally, when the roof is laminated, the topcoat, which satisfies the GRP roofing standards, is applied and the roofing itself is done.