GRP Roofing

ProGRP (Glass Reinforced Polyester) is a new, advanced liquid applied GRP flat roof system that has been specifically engineered for flat roof applications, such as extension roofs and garages. This new technology lasts 5 years longer than the average flat roof, is resistant to all types of weather and is provided in the same price range.

If you have a larger roof size than our base kits provide for, or if you have specific requirements, please feel free to contact us as we can provide something bespoke for you. We also stock skylights that go perfectly with a flat roof system; they can be purchased at one of our branches, or you can order them over the phone and we can get them delivered within a 40-mile radius of our branches.


ProGRP is very versatile and can be applied to anything from small domestic buildings to large industrial environments and its 25 year guarantee will ensure it stays there for a long time. ProGRP roofing is available in two grades of CSM (chop strand matting) depending on the nature of your building. If you’re expecting high foot traffic on your roof, 600gsm CSM will keep your roof fully intact throughout. For a smaller and perhaps more domestic installation, 450gsm CSM is the way to go.


A ProGRP roof is a wet laid, single ply GRP laminate made up of two layers of catalysed resin sandwiching and the layer of CSM of your choice, as above. It is then applied to a new OSB T&G3 board and profiled GRP edge trims are applied to the roof edges abutments. Finally, the roof is finished with a coat of catalysed pigmented top coat.

This system is also referred to as a cold roof, which means the insulation is laid between the joists and supported by the ceiling.

Please ensure that the decking boards are dry before installation, as otherwise the system will not bond well and will de-laminate.

Main Components

Primary components are:

  • Resin – available in 10kg and 20kg cans
  • Top coat resin – available in 10kg and 20kg cans
  • Liquid catalyst (hardener) – available in 1kg and 5kg containers
  • Chopped Strand Matting – available in various lengths and 450gsm or 600gsm
  • Edge trims – pre-formed in 3M lengths

There is a also a wide range of ancillaries and application tools – please browse our list of products for full options.

What are the benefits of GRP roofing?

  • There is a range of profiled edge trims to suit all applications.
  • Low styrene emission resins.
  • UV resistant.
  • Fully resistant to wind uplift.
  • An anti-slip resistant finish is available.
  • Fire retardant (BS476 PART3 EXT.F.AB).
  • 25 year materials guarantee (only when installed by Cromar approved tradesmen)
  • No joints, no seams and no leaks.
  • Heat resistant
  • Storm proof
  • Frost proof
  • Impact resistant
  • Durable enough to resist foot traffic

 Please browse our range to find out what’s best for you and use our guides and tips articles to find out more information.

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