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Fibreglass Roofing in Cardiff & Across Wales
Wales Roofing & Guttering provides fibreglass roofing in Cardiff and throughout Wales. GRP flat roof installation, repair, and replacement — all backed by a written guarantee.
TRUSTED BY 100s OF HOMEOWNERS ACROSS WALES
TRUSTED BY 100s OF HOMEOWNERS ACROSS WALES
Why GRP Fibreglass
Roofing Works in Wales
Why GRP Fibreglass
Roofing Works in Wales
GRP — glass reinforced plastic — has been the go-to flat roofing material across the UK for over two decades, and for good reason. In Cardiff and the wider Welsh valleys, where rain is a near-permanent fixture and coastal gusts can be harsh, a roofing system that repels water without joints, seams, or overlaps makes practical sense.
Fibreglass roofing creates a rigid, one-piece membrane that bonds directly to the roof deck. There are no seams to split, no laps to lift, and no adhesive joints that can weaken over time. Once the resin has cured, you have a single continuous waterproof shell — tested to last well beyond 25 years under normal conditions.
Unlike traditional felt, which tends to blister and crack within a decade (particularly on south-facing extensions exposed to UV and thermal movement), GRP holds its shape. It does not absorb water. It handles impact well. And the topcoat can be colour-matched, so the finished result looks considered rather than purely functional.
25+
Year Lifespan
100%
Seamless & Jointless
Written
Guarantee on All Work
Free
No-Obligation Surveys
Fibreglass Roofing
Installation — How It Works
Fibreglass Roofing
Installation — How It Works
Every fibreglass roof we fit follows a methodical process. Cutting corners at any stage compromises the end result, so we stick to the correct sequence every time.
The existing roof covering is stripped back first. If the timber decking beneath has gone soft or rotten, we replace it — there is no point laying a new GRP system over boards that cannot support it. Once the structure is sound, we fix new 18mm OSB3 boarding across the full area to give a smooth, stable surface for the fibreglass to bond to.
Then comes the laminating stage. We lay glass fibre matting across the entire roof, working it carefully into corners, upstands, and drip edges before saturating it with catalysed polyester resin. This step is what separates a roof that lasts five years from one that lasts thirty. Too little resin and you get dry patches; too much and it pools. The ratio needs to be right.
After the base layer has cured, we apply the UV-resistant finishing topcoat — typically dark grey, though other colours are available. Trims, drip edges, and fillets are all formed in GRP as well, mechanically fixed rather than stuck down with sealant. The entire perimeter ends up watertight with no weak points.
On a typical domestic garage or extension in Cardiff, the full process takes between one and three days depending on weather and complexity.
Where We Install
Fibreglass Flat Roofs
Where We Install
Fibreglass Flat Roofs
GRP fibreglass is suitable for most flat and low-pitch roof structures. Below are some of the most common applications we carry out across Cardiff, Newport, Pontypridd, and the wider South Wales region.
Garage Roofs
Older garages with failing felt or asphalt coverings gain hugely from a GRP overlay or full replacement. The result is a tough, sealed surface that will not need attention for decades.
Home Extensions
Rear and side extensions with flat sections need a covering that copes with maintenance foot traffic and thermal movement from below. GRP manages both without issue.
Bay Windows & Dormers
These smaller areas are often the first to leak because the original lead or felt has cracked. Fibreglass provides a lasting fix that does not rely on caulking or patchwork.
Balconies & Walkways
For areas with regular foot traffic, we specify heavier-grade matting and a non-slip topcoat. GRP balcony decking is popular in coastal areas around Penarth, Barry, and the Vale.
Why Choose Wales
Roofing & Guttering
Why Choose Wales
Roofing & Guttering
Choosing a contractor for fibreglass roofing is not something most people do regularly. We think it comes down to a few things worth spelling out.
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No Subcontractors
We do not subcontract. Every person on your roof is employed by us directly, which matters when decisions need making on-site. You deal with the people doing the work — not someone relaying messages from a distance.
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Trusted Materials, Properly Fitted
We source GRP materials from established UK suppliers. Budget resins and lightweight matting might lower a quote by a few pounds per square metre, but they rarely hold up long-term in a climate as wet as ours. We prefer to quote a fair price for materials that last.
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Transparent from Start to Finish
If we find anything unexpected once the old covering comes off — damaged timbers, poor falls, inadequate insulation — we explain the options and agree costs before continuing. Every job is documented with photographs so you have a clear record of the work carried out.
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No Subcontractors
We do not subcontract. Every person on your roof is employed by us directly, which matters when decisions need making on-site. You deal with the people doing the work — not someone relaying messages from a distance.
![]()
Trusted Materials, Properly Fitted
We source GRP materials from established UK suppliers. Budget resins and lightweight matting might lower a quote by a few pounds per square metre, but they rarely hold up long-term in a climate as wet as ours. We prefer to quote a fair price for materials that last.
![]()
Transparent from Start to Finish
If we find anything unexpected once the old covering comes off — damaged timbers, poor falls, inadequate insulation — we explain the options and agree costs before continuing. Every job is documented with photographs so you have a clear record of the work carried out.
Recent Fibreglass Roofing Projects Across Wales
A selection of GRP fibreglass roofing projects completed across Cardiff and wider Wales — from garage re-roofs and extension coverings to bay window tops and balcony installations.
GRP Garage Roof — Cardiff
Extension Roof — Bridgend
Bay Window GRP — Penarth
Trusted GRP Roofers
Serving Cardiff & All of Wales
Trusted GRP Roofers
Serving Cardiff & All of Wales
We are based in Cardiff and carry out fibreglass roofing projects across the whole of Wales. Newport, the Vale of Glamorgan, Bridgend, Swansea, Pontypridd, Caerphilly, Penarth, and Barry all fall within our regular working area — though we travel further afield for larger projects.
The same standards apply on every site. Whether it is a terraced house in Splott or a detached property near Cowbridge, we follow the same preparation, lamination, and finishing process. Domestic properties, commercial premises, new builds — the building type changes but the quality of the workmanship does not.
Most of our fibreglass roofing work comes through recommendations and repeat customers. We turn up when we say we will, we keep the site clean, and we do not leave before the job is properly finished. If something is not right, we would rather flag it during the work than have you ring us six months later with a problem that could have been avoided.
Areas We Cover
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Cardiff
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Merthyr Tydfil
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Newport
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Swansea
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Carmarthen
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Bridgend
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Port Talbot
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Porthcawl
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Llanelli
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Ammanford
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Burry Port
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Gorsenion
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Pyle
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Pencoed
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Cowbridge
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Barry
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St. Mellons
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Caerphilly
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Pontypridd
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Porth
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Tonypandy
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Blackwood
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Pontypool
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Cembran
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Caerleon
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Risca
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Rogerstone
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Abertillery
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Brynmawr
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Ebbw Vale
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Tredgar
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Rhymney
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Aberdare
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And All Surrounding Areas
Areas We Cover
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Cardiff
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Merthyr Tydfil
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Newport
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Swansea
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Carmarthen
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Bridgend
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Port Talbot
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Porthcawl
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Llanelli
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Ammanford
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Burry Port
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Gorsenion
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Pyle
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Pencoed
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Cowbridge
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Barry
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St. Mellons
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Caerphilly
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Pontypridd
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Porth
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Tonypandy
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Blackwood
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Pontypool
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Cembran
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Caerleon
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Risca
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Rogerstone
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Abertillery
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Brynmawr
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Ebbw Vale
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Tredgar
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Rhymney
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Aberdare
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And All Surrounding Areas
Book a Free Fibreglass Roof Survey
Whether you need a new GRP flat roof on an extension, a fibreglass replacement for a failing garage covering, or a repair to an existing system — we can help. Every survey is free, every quote is detailed, and all completed work is backed by a written guarantee.

GRP Trims
All trims and edge details are formed in fibreglass for a fully watertight perimeter.
Fibreglass Flat Roof
Seamless GRP membrane bonded directly to the roof deck for lasting waterproof protection.
Gutter Replacement
New guttering fitted alongside your fibreglass roof for complete rainwater management.
Book a Fibreglass Roof Survey
And Receive a Free Estimate
Fibreglass Roofing
Frequently Asked Questions
Fibreglass Roofing
Frequently Asked Questions
Common questions about GRP fibreglass roofing. If there is anything else you need to know, get in touch and we will be glad to help.
How long does a fibreglass roof last?
A properly installed GRP fibreglass roof will typically last 25 to 30 years or longer with minimal maintenance. The resin and glass fibre composite forms a tough, weather-resistant membrane that holds up well in the Welsh climate — including persistent rain, coastal salt air, and fluctuating temperatures.
How much does fibreglass roofing cost in Cardiff?
Costs vary depending on the roof’s size and complexity, access requirements, and whether insulation is included as part of a warm roof system. As a general guide, GRP flat roofing tends to fall between £70 and £150 per square metre for materials and labour. We provide free, no-obligation quotes specific to your property — contact us for a detailed estimate.
Is fibreglass roofing better than felt or EPDM?
GRP fibreglass produces a rigid, seamless finish that is harder-wearing than felt and does not rely on adhesives the way EPDM rubber does. It is fire-resistant, strong enough to take foot traffic, and generally lasts longer than both alternatives. The upfront cost is higher, but many property owners find it works out more cost-effective over the roof’s full lifespan.
Can fibreglass roofing be installed in wet weather?
GRP roofing needs dry conditions during the laminating and curing stages. The resin will not bond correctly if the decking is damp or rain falls before the topcoat has fully cured. We schedule installations around the weather forecast and will always let you know in advance if conditions are not suitable.
What maintenance does a fibreglass roof need?
Very little. An annual visual check and a wash down with mild soapy water is usually all that is required. Clearing leaves from perimeter gutters helps prevent water backing up under the roof edges. Unlike felt, GRP does not crack, blister, or degrade under UV exposure at the same rate.
Do you offer a guarantee on fibreglass roofing?
Yes. All fibreglass roofing installations carried out by Wales Roofing & Guttering come with a written guarantee. The length of the guarantee depends on the specification and system used, and we confirm this in your quote before any work begins.
Need Fibreglass Roofing in Cardiff or Anywhere in Wales?
From single garage re-roofs to full GRP installations on extensions and balconies, we bring the same attention to detail and quality materials to every project. It is the work beneath the surface — the preparation, the resin ratio, the trim detailing — that determines how long a fibreglass roof actually lasts. That is where our focus is.
Call us for a free, no-obligation quote or fill in the contact form and we will get back to you promptly.
