Polyroof’s 185 system is the UK’s leading GRP roofing system and has become synonymous with premium performance. Polyroof 185 was the first ever fibreglass system to receive BBA certification and has been installed on roofs and balconies since 1984. Always applied to a Polyroof approved OSB3 or plywood deck, the system carries a 30 year durability rating and provides an exceptionally tough and hard-wearing membrane. our flat roofing materials are long-lasting and durable, ensuring that your roof lasts a lifetime.

Extra-Tough and Hardwearing GRP Roofing System


  • The 185 system is always applied to Polyroof approved plywood or OSB3 boards.
  • Refurbishments: Usually used on roofs involving strip-and-replace works.
  • New Build: Ideal for any new build timber roof applications.
  • Roof Designs: Ideal for use as part of a warm or cold deck roof design.
  • Balconies & Walkways: Available with a BBA approved extra tough anti-slip finish for trafficked areas.


  • Ideal for small to medium sized projects requiring an extra tough, durable and highly impact-resistant finish.
  • Extremely hardwearing and can withstand regular foot traffic without additional protection
  • Available in a wide range of colours and finishes.
  • Fire performance: Classified as BROOF(t4), the top rating achievable for a flat roof system and designating Polyroof 185 as unrestricted under UK the national Requirements (see Section 7 of BBA Certificate 91/2604).
  • BBA durability rating of up to 30 years.
  • Carries Polyroof’s trusted Accredited System Guarantee.
  • The guarantee is supported for 20 years by an independently administered trust fund with additional annually renewable insurance as standard.
  • Standard colours are Dark Battleship Grey, Light Battleship Grey, Lead Green, Dark Grey and Havana Brown (see our Colours & Finishes page for more options and further details) colours-and-finishes-flat-roofing
Polyroof 185 System BrochurePolyroof 185 Specification Download
BBA Certificate (91/2604)BBA Certificate Download

Polyroof Outline Specifications

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Why Should You Use GRP Roofing?

GRP Roofing is one of the most reliable and cost effective roofing options on the market today.

Also known as Fibreglass Roofing, it uses quality materials to help make it weatherproof and requires little to no maintenance, making it a perfect choice for any home.

GRP (Glass Reinforced Plastic) is a fantastic material for waterproofing, keeping the weather outside and protecting the contents of your home in the process. The tough and hard-wearing nature of GRP Roofing should last for 30 years, which explains why it has become one of the most popular roofing options over the last few years.

With GRP Roofing, you can enjoy choosing from a range of colours and finishes to best suit your home, with options such as Havana Brown, Dark Battleship Grey and Lead Green available. Being able to find a colour will help the roof to blend in with the rest of the house, giving it a slick look that complements the appearance of your home.

There is no need to worry about different roof shapes either, as the material can easily moulded to perfectly fit the shape of any roof. This kind of flexibility is another reason why Fibreglass is becoming the number one choice for flat roofing

GRP Roofing can be used for both domestic and commercial properties, being suitable for the likes of sheds, garages, extensions and balconies as well as schools and hospitals.

The installation of Fibreglass Roofing doesn’t require any heating tools or hot works to complete either, making it one of the safest installation processes.

Despite being so light and easy to install, it’s very durable and impact resistant, making sure there is no chance of any leaks. When combined with new insulation as part of a “warm roof” design, you can save considerable amounts of money on your energy bills too. GRP is also fully compatible with solar panels and green roof systems, making it a great choice for sustainable roof solutions.

Cleaning the GRP membrane is quick and easy as well, with a simple clean with washing up liquid and warm water being more than enough to keep it looking brand new.

As far as installation goes, the process begins with a new timber deck – either OSB3 or approved plywood. This acts as a substrate to which the base resin is applied. Whilst the resin is wet, chopped strand matting reinforcement is embedded to create an exceptional strong membrane.

Once this layer dries in around 30 – 60 minutes, a top coat pigmented to your choice of colour is applied to give the roof a glossy, attractive finish and extra UV resistance and durability.

Although DIY solutions are available on the market, it is prudent to engage a professional roofing contractor to carry out the works. Look for contractors who are approved under a reputable manufacturer’s scheme, such as Polyroof’s ISO 9001 certified Approved Contractor Network.

Make sure to ask for BBA approval on the materials to be installed on your roof to ensure they comply with regulations and avoid any future headaches if you come to sell your property. Lastly, make sure to look at what is and isn’t covered under the guarantee – one 20 Year Guarantee can be very different to another!

Does it simply cover the materials and the guarantee is void if it’s a workmanship fault? Or does it cover both labour and materials?

Have You Got Any Questions About GRP Roofing?

If you’d like to learn more about the specifications of GRP Roofing or discuss any projects you may be planning, feel free to get in touch today. We’d be more than happy to answer any questions or queries you may have.

Polyroof GRP Drip Trim

Drip Detail Download (PDF) Download (DWG)

Polyroof GRP Upstand Trim

Upstand Detail Download (PDF) Download (DWG)

Ventilated Perimeter

Ventilated Drip Download (PDF) Download (DWG)



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Nautica, Hampshire

This attractive new apartment block development on the south coast of England required a thermally efficient roof design that could also incorporate photovoltaic (PV) cells. Due to the strong winds the roof was subjected to, the client required the PV cells to be mechanically fixed into the roof structure. Having worked with Polyroof on various new build developments in the past, a solution was sought that could meet all of the environmental and energy demands whilst also providing durable and fully guaranteed waterproofing…
[Read more]


Explorer Court GRP Roof

Explorer Court, Plymouth

The project included the waterproofing of over 400 square metres on the main barrel roof and lower penthouse balconies for a highly successful and NRFC award winning development by Barratt Homes. The main roof was designed with a wave effect, with an internal radius of 5672mm. For the balcony areas, the designer specified decorative timber decking over the waterproof membrane, which meant that the membrane had to be durable enough to bear the weight from the decking… [Read More]


Flush-Fitted Skylight for Orangery Roof

The Polyroof 185 system was specified as it provided the client with a seamless and durable waterproofing solution that would look stylish and modern, and could be incorporated with the rest of the building’s design. A key feature to the design of the roof was a large glass skylight that the architect designed to be level with the surrounding roof, creating a visually striking and modern look to the roof. However this presented a challenge as an upstand to the rooflight was still required to ensure a fully weatherproof detail could be formed… [Read More]


Domestic Balcony GRP Roof

Domestic Balcony Projects

The Polyroof 185 system has been specified on numerous balcony and walkway areas across the country. Carrying an insurance-backed guarantee for 20 years, the system provides a BBA approved anti-slip finish that is extremely tough and long lasting. As is often the case, the cost effectiveness and the aesthetics of the balcony are of upmost important to the client. This modern balcony design was incorporate a coloured finish as chosen by the client and an attractive glass balustrade around the perimeters… [Read More]


Spiral Roof for Woodland Trust

As described by the Woodland Trust, Glen Finglas is a great expanse of ancient woodland, lochs and open heathland, sitting at the heart of Loch Lomond and The Trossachs National Park and home to one of the best examples of upland wood pasture in Scotland. The newly constructed Gateway Building was designed to blend in with the surrounding woodlands and featured a circular timber-clad exterior with a spiraling, curved roof. The Woodland Trust chose Polyroof to provide a guaranteed waterproofing solution that would complement the aesthetics of the building… [Read More]

185 System Application Video

This video produced in conjunction with the LRWA demonstrates an application of flexible and resistant polyesters using Polyroof’s 185 System.

Polyroof GRP Flat Roof
Discovery Centre Flat Roof
Polyroof's Fibreglass Roofing System
Balcony Flat Roof by Polyroof
House with GRP Flat Roof
Polyroof 185 System in Action
GRP System for Balcony Roof
GRP Roofing System being used on Apartments
GRP Flat Roofing System
Polyroof's Flat Roofing System
GRP Roof on Garage
185 GRP Roof Application in Progress
GRP Wave Roof
Fibreglass Flat Roof Application on Apartments
Spiral Flat Roof from Polyroof
GRP Spiral Roof
Polyroof 185 GRP Roofing System
Flush-Fitted Skylight
Polyroof Fibreglass Roofing
GRP Flat Roofing System
GRP Flat Roof Application