GRP Fibreglass

GRP Fibreglass - Versatile, Adaptable and Resistant

GRP (Glass reinforced polyester) or Fibre-glass has become a very popular choice for flat roofs in the UK commercial market. It's stunning good looks and tough finish are a winning formula that waterproof buildings of all types whether old or new. Each new roof is laid onto a solid 18mm OSB3 deck which gives GRP its superior strength and an advantage over many other flat roof systems. This system is by far the toughest flat roof on the UK market. GRP is so versatile around complicated detail, and it shrugs off the harsh British weather in both the Summer and Winter.

GRP Fibreglass roofs, when professionally installed by our fully trained and accredited fitters.

Add that to the fact that you will most likely never need to have this roof replaced again, it's worth doing it properly the first time.

Our GRP roofs are expected to last at least 50 Years and come with a Bombproof 25 Year, no quibble, fixed guarantee.

Do you have a roof that has a lot of detail going on? Steps, parapet walls, rooflights, pipe penetrations? GRP is by far the best system to expertly mould around each detail with a great looking hard shell that clings to each detail keeping out the rain and the cold.
We all want our buildings to look as amazing as possible and you will not be disappointed with the stunning good looks of your new GRP Fibreglass roof.

GRP is also the toughest system we fit and can withstand impacts from falling sharp objects. GRP when correctly fitted forms a tough hard skin that is similar to the hull of a boat - very difficult to damage. It also has an extremely high tolerance to heat and flame and carries the highest fire-rating of any flat roofing system on the market.
Roof maintenance and foot traffic will cause no problems on a GRP roof.

As with any Flat Roof system, there will also be negative opinions which can negatively influence building owners into believing that it is a flawed system.

At Stace Roofing we offer 5 flat roofing systems and I have personally heard it said that every single one of them is destined to fail or is not a good quality lasting system. This is almost always biased information from someone that is trying to discredit a particular system or from someone that has been on the wrong end of a bad job.
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GRP Myths

  • GRP does not crack or split - If it is fitted properly
  • GRP does not fail if you use the right deck and fix it down properly
  • GRP does not let in water through pinholes if you used enough resin
  • GRP does not fail after 10 years, it lasts over 50 years if the whole project has been specified, planned and fitted CORRECTLY by fully trained fitters.
Our main supplier fitted a GRP roof 54 years ago at his fibreglass car building factory in the North-West of England. It's still in action and still doesn't leak!

We have been fitting these roofs since 1999 and we still always look for improvements in the fitting process every year as technology advances.

Since 1999 we have created a fitting process that is as perfect as it possibly can be.
There are fitters out there giving GRP a really bad name because of the following reasons:
  • They are not adequately trained. Some GRP systems are available to buy off the shelf in most DIY merchants and the training is usually a Youtube video.
  • They do not know how to run a business. All they want to do is make a days wages, they are not investing in themselves and they most likely won't be around in the future if you ever have problems.
  • They try to save as much money as possible by skimping on materials. They use the cheapest stuff they can get, and don't use enough resin which leaves your GRP with air pockets, pinholes and it then becomes porous and sucks in water to the inside of your building.
  • They try to do the job as fast as possible so they can get onto the next job and make even more money. They skip the essential work needed to ensure the fibreglass mat is fully saturated. They allow it to set prematurely, and then paint the topcoat over the shoddy laminate to hide it. (this will fail within 6 years)
  • They are fairly sure you are not going to get up on the roof to check their work.- We encourage it.
Andy's note: All of the roofing systems on the British market are fit for purpose as long as they have been fitted to the manufacturer's guidelines by a competent and trained fitter. We also recommend that a product that has been tested through the BBA Weather testing process is used.

Every single flat roofing system on the market will fail if it hasn't been fitted properly.

But that doesn't mean that every system is the same, or is suitable for every roof or property owners requirements.

So we are completely unbiased when recommending a system, we always recommend the right system for the right type of roof or budget.
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Your Guarantee

Once your roof has been fully checked and signed off, you will get a full written guarantee from Stace Roofing. Your guarantee from us will include a no quibble repair policy should anything go wrong with your roof for the period stated on your quotation and invoice. We will pay for any scaffolding that is needed to get back onto your roof and all of the labour and materials needed to fix the defect. In the highly unlikely event that any problems arise in the future, you will not need to worry.

Included in your standard guarantee:
  • The Roofing Materials - Any defects covered by Stace Roofing and the manufacturer.
  • The workmanship - covered by Stace Roofing
Included in your Premium Guarantee:-
  • The Roofing Materials - Any defects covered by Stace Roofing and the manufacturer.
  • The workmanship - covered by Stace Roofing
  • Full deposit protection. An insurance policy that starts as soon as your deposit has been received. (Competent Roofer Scheme - Insulated Refurbishment work only)
  • Building Regulation Compliance Certificate to cover all the work. (Competent Roofer Scheme - Insulated Refurbishment work only)
  • Post Completion Insurance Backed Guarantee covering all work for 10 years. Covered by Certass (Competent Roofer Scheme - Insulated Refurbishment work only)
Premium guarantees are issued as standard with all fully insulated refurbishments and re-roofs. Please see our Warm roof and Insulation details for more information on how your roof might fall under the Competent Roofer scheme and get a premium guarantee.
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GRP Benefits

GRP is the best choice for you if:
  • You want the best looking roof covering that will complement the appearance of your building
  • You want the longest lasting roof covering that you will probably never need to replace again
  • You want the toughest roof covering that will withstand any impact from falling roof tiles and objects
  • You have a roof that has complicated detail that could cause future problems
  • You want a roof that has NO JOINTS OR SEAMS
  • You want a risk-free, flame-free installation
  • You want virtually zero maintenance for the next 50 years
  • You want no interuption to the business activities of your building due to water ingress
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What is Your Next Step?

Click here to book a survey
Click here to get a quote
Click here to request a call back
Or call us on 01664 431370 or freephone 0800 555 5555

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GRP Technical Information

  • GRP is environmentally sustainable and completely safe to install. There's no need to use a naked flame during the installation, so your risk of a fire during the installation is zero.
  • It is rated A/A+ in the BRE Green Guide, which means that it is produced without any negative impact to the environment or the planet.
  • Over 1 million square metres of this system have been laid in the UK in the past 20 years. This demonstrates the appeal and durability of the system has been proven year on year.
  • Your new Fibreglass roof will be maintenance-free, Eco-friendly and will require virtually no additional work or up-keep throughout its life-span.
  • Without a doubt, it is the hardest and toughest system we install and its lifespan will depend on which grade you choose.
  • GRP can come in any color on the RAL colour chart by simply mixing the clear topcoat with a coloured pigment. Our tip on this is to choose a neutral colour to blend in with any brick, stone or other building material. Dark Grey for instance is our preferred choice as it's timeless understated presence will remain fashionable with any future choice of window color or other change to the exterior of your building at any point during its 50 Year lifespan.
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Your Laminate Options

1x 450gsm 20 Year (Non BBA Approved)
1x 450gsm 25 Year BBA Approved
1x 600gsm 30 Year BBA Approved
2x 450gsm 40 Year BBA Approved

(All of the above systems are expected to last double the guarantee periods).

Colours: Any colour possible.
Coverable: Ok for slabs, decking, green roofs with additional layer of laminate required - (Subject to ELD leak test)
Detail suitability: Perfect for Complex detail
Fire resistance: Fire retardant to BS 476 part 3 the highest rating available for any flat roofing system.
Edge Trims: GRP factory made. Big choice of colours.
Warm-Roof Compatible: Yes, OSB3 boards fixed onto foil-faced PIR or fully adhered onto tissue-faced PIR boards
Warranty: Up to 40 Years
Life Expectancy: 50+ Years
UV resistant: Yes
Root Resistant: Yes
Weight/m2: 2.4kg 450gsm membrane + 12.15kg OSB3 18mm Deck = 14.55kg total (based on 450gsm glass)
Green Roof Compatible: Yes, with 2x layers of 450gsm laminate
Inverted Roof: Yes
Maintenance: Low/None
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How is a GRP Fitted?

118mm OSB3 TG4 deck - TG4 is a tongue & grooved board on all 4 sides, once it has been laid and fixed, its interlocking joints become filled with the polyester resin to ensure a totally solid base is formed without any risk of cracking on the GRP layer as the building moves. We recommend that a new, clean and totally dry deck is used. It is not recommended that the flat roof deck is fitted and then worked on by other trades before fibreglassing. Dirt and dust can cause a film that will prevent the resins from forming a strong bond with the deck.
(Andy's Note:WBP ply-board or Marine Ply is not suitable as a deck for most adhered or glued systems. This is because the top layer of most Ply boards contain hardwood oils which unless sealed with a primer to prevent from future leaching, will cause delamination of the new GRP layer from the deck - we have seen many older GRP roofs fail because of this.)

trimGRP Trims - There is a pre-formed factory made trim for every possible type of detail or junction. These trims are stapled to the perimeters of the roof before the fibreglass is laid. (Andy's note: Many failures in GRP roofs have been due to home-made trims or trims being incorrectly fitted.)

glassmat
Fibreglass Mat - This usually comes in 2 weights, 450gsm (grams per square metre) and 600gsm. The heavier mat is for roof terraces or can be used to get an additional 5 years on the guarantee for standard roofs. The strands in the fibreglass mat are hollow tubes that suck in the resin to give superior strength.A double layer of 450gsm mat should be used if you are covering your flat roof with decking, slabs, artificial grass or Sedum living roofs.
(Andy's note - A common failure of GRP roofs is caused by inexperienced contractors who do not put enough resin onto the mat. Unless the mat is totally saturated in resin, it will be porous and weak. Once the porous mat is exposed to the atmosphere, the hollow tubes suck in water, and when it freezes in the winter, it will expand and cause total failure of the GRP layer. This failure can take around 5-6 years to become evident and will always result in the roof having to be re-fitted.)

resinPolyester Resin - This is the liquid that the mat is saturated with. A generous coat should be applied both underneath and on top of the mat to ensure all of the fibre-glass strands are free of air pockets and pinholes.

(Andy's Note - Pinholes are caused when the mat is not fully saturated by the resin. This can cause a direct point of entry for water ingress, especially over joints in the timber deck)
topcoatPolyester Topcoat - This is also known as the Gel coat. Topcoat comes in many colours and has additives that give it more flexibility due to it not having a mat to reinforce it. This coat should be applied in a thin layer but not see-through, and should be applied as soon as possible after the GRP laminate coat has been laid.

(Andy's note - The GRP waterproofing laminate can take up to 30 days to cure completely. After this time, the topcoat will not adhere properly unless the laminate is treated with a chemical to soften the surface and allow the chemical in the topcoat to bond with the laminate.)

2Overlay Existing Roofs
In some cases, GRP can be directly overlaid onto existing flat roofs without the need for a new deck using our overlay system. The roof will need to be suitably prepared and cleaned and then a primer applied to seal any porous surfaces. This system works well on asphalt, concrete and felt roofs.



compComplicated DetailGRP can be used in many awkward situations. It is incredibly versatile and will form around any shape or object within reason. It can be used as a replacement for lead box gutters and lead central valley gutters.
Because it doesn't expand at the same rate as lead, complicated joinery steps in these gutters are not necessary, keeping building costs down.

greenGreen Sedum and living roofs
GRP is compatible for Green Sedum Living Roofs. It's strength and superior waterproofing qualities make it perfect for all types of intensive and extensive green sedum, brown and wildflower roofs. 2 layers of 450gsm mat are essential for roofs of this type which are classed as "submerged roofs" because they are constantly underwater.

terraceRoof Terraces and Balconies

Our Fibreglass roofs make amazing roof terraces. GRP is 100% puncture resistant allowing heavy metal furniture to be placed directly onto its surface without any negative impact. Beautiful coloured quartz grains can be directly adhered to the top layer of GRP to give a stylish non-slip coating. Or you can lay decking or slabs too.

simulLead Simulation & Replacement

GRP can be used as a replacement for lead roofs that are prone to lead-theft. It has no scrap value and is very difficult to remove once fitted by experienced installers.

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GRP Summary

  • A full BBA certification is available on most of our GRP systems
  • 50-year Plus Life Expectancy-so no more time spent on maintenance or worrying about leaks damaging your room below.
  • No seams, welds or joints AT ALL-all but guarantees no more leaks as the joins are normally the weakest part of a roofing system.
  • Great looking finish. Over 1000 colours to choose from-meaning you can make your new roof look just the way you want to.
  • Only fitted by fully trained and vetted Contractors-which ensures you'll get a great job done by a skilled craftsman who knows what they are doing. Not recommended for use by the DIY Sector
  • Versatile. Will mould around any shape, penetration or obstruction.
  • Flexible. This membrane will expand to allow for building movement so It won't split and cause leaks in the future.
  • Flame-Free Installation. No heat or welding on site-which means No fire risk to your property over the years there have been many house fires caused by "torch-on" felt roofing systems due to un-trained installers and lack of health & safety training.
  • Maintenance Free-so more time to enjoy your free time rather than fixing your flat roof leaks
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What our clients say

How refreshing to deal with a thoroughly professional company who understand customer service and quality work. The team treated my house as a home not a building site and nothing was too much trouble. I would have no hesitation in recommending them

Simon King

It was a pleasure dealing with a Company that provides a highly professional and considerate service. I have received a number of (good) comments regarding the works from neighbours and also a note through the front door - all of whom asked who was carrying the work and for your contact details which I have passed on - I hope you get at least one enquiry from those.

Simon Barnes

Stace Roofing provide a quality professional service delivered by skilled staff who are polite, considerate and leave the site clean and tidy.

Mr P Roffey

Stace Roofing have consistently supported our works with excellent workmanship, friendly advice, great flexibility and assistance above and beyond the call of duty, providing a user friendly non-contractual service, favouring open and honest discussion.

Mr Martin Kempler