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Is GRP better than EPDM

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  • GRP Roofing, Comparing EPDM and GRP, Benefits of GRP over EPDM, Traditional Felt, EPDM
  • Posted date:
  • 15-08-2023
Is GRP better than EPDM

Is GRP better than EPDM? If you are considering a new roof installation you will want to find out the best materials to use. Find out if GRP or EPDM is right for you. Flat Roofers Basingstoke provide GRP fibreglass roofing installations for Andover, Basingstoke, Winchester and the surrounding areas.

EPDM vs GRP Flat Roofing

When it comes to choosing the right material for your flat roof, you may find yourself debating between two popular options: EPDM (Ethylene Propylene Diene Monomer) and GRP (Glass Reinforced Plastic). Both materials have their unique characteristics and advantages, making the decision a crucial one for the longevity and performance of your roof.

EPDM is a type of synthetic rubber roofing membrane known for its exceptional durability, flexibility, and resistance to UV radiation and weather elements. The single-ply EPDM sheets are typically installed in one continuous layer without the need for joins, making it an attractive option for those seeking a seamless and watertight roofing solution.

On the other hand, GRP, also known as fibreglass, is a composite material made by reinforcing plastic with fine glass fibres. GRP flat roofs are renowned for their strength, weather resistance, and long-term durability. The joint-less finish and customisable colour options make GRP a popular choice among homeowners and builders alike.

Is GRP better than EPDM? | GRP Fibreglass Roofing Andover, Basingstoke, Winchester

A Comparison of EPDM and GRP

Material Quality

EPDM roofing is crafted from a highly flexible and rubber-like material, making it an excellent choice for roofs with uneven surfaces. Its unique composition allows moisture and heat to escape from the roof space while effectively preventing the entry of moisture, smoke, and vapours. However, one potential drawback is the possibility of shrinkage over time, which could impact the integrity of the roofing.

On the other hand, GRP, commonly known as fibreglass, offers remarkable flexibility and lightweight properties, making it ideal for roofs with more complex shapes. GRP creates a jointless and tightly bonded finish, ensuring complete sealing against moisture infiltration. Its robust composition makes it a reliable choice for various roofing applications.

Durability & Lifespan

EPDM roofs boast an impressive lifespan when correctly installed, surpassing that of other traditional roofing materials. With an average longevity of 25-30 years, EPDM roofs can even last up to 50 years with proper maintenance and care. Its exceptional durability ensures resistance to blistering, cracking, and rot caused by thermal movements, contraction, and expansion.

Similarly, GRP roofing offers fantastic durability, with an average lifespan of at least 25-30 years, given it is installed correctly. Its lightweight nature does not compromise its strength-to-weight load-bearing performance, making it highly resilient against harsh weather conditions, with minimal wear and tear or structural pressure. GRP is further resistant to moss growth and offers superior corrosion resistance.

Weather Resistance

Weather Resistance - Is GRP better than EPDM?

EPDM flat roofing excels in weather resistance, being highly waterproof and seam-free, minimising the risk of leaks and water seepage. It boasts exceptional resistance to UV rays and can adapt well to expansion and contraction caused by temperature fluctuations.

Similarly, GRP roofing offers outstanding weatherproofing capabilities. When installed correctly, it becomes completely leak-proof and watertight, withstanding even the most intense downpours and stormy weather. The fully bonded structure and seamless fabrication prevent any moisture penetration.


EPDM roofing installation is generally straightforward, particularly for professionals well-versed in the process. It employs flame-free application, with a single sheet of EPDM glued to the roof decking using a wet bonding adhesive. Trims are then fitted to create a durable and clean finish.

However, improper installation may lead to future problems, underscoring the importance of hiring experienced contractors.

Similarly, GRP roofing installation requires a certain level of expertise, though it is manageable for knowledgeable individuals. The process involves applying layers of resin and fibreglass strands, followed by a protective topcoat to ensure weatherproof durability. GRP installation, however, can take longer compared to EPDM, and it cannot be applied during wet conditions, necessitating strategic planning.

Maintenance & Repairs

EPDM roofing generally requires minimal maintenance to maintain its high-quality performance. Small tears or holes can be easily repaired by applying a sealant to the damaged area or by using a patch, leaving virtually no visible signs of damage. Cleaning EPDM roofing is a simple process involving sweeping off debris and using a rubber roof cleaner, followed by mopping the roof area.

Similarly, GRP roofing, due to its high durability, typically requires less frequent repairs. While less likely to break, fibreglass may be slightly more challenging than EPDM to repair if needed.

In the case of damage, GRP can be patch repaired by sanding down and installing a fibreglass patch, topped with resin and topcoat. Cleaning GRP roofs is equally straightforward, involving the removal of debris and using a long-handled mop with warm soapy water or even a pressure washer for more effortless cleaning.


Cost - Is GRP better than EPDM?

EPDM roofing is generally more affordable than other materials, especially considering its long-lasting durability, which reduces the need for frequent replacements and maintenance. Its straightforward installation process requires fewer complex tools, making labour costs more reasonable.

In contrast, GRP roofing is often priced higher due to its premium quality and impressive lifespan. The installation process demands more time, tools, and products, contributing to the overall cost. However, its exceptional durability means fewer repairs are required, minimising potential long-term expenses.


EPDM roofing offers a simplistic appearance, akin to a large piece of dark rubber. Some homeowners may find this less visually appealing, while others appreciate its easy maintenance and the fact that it is not visible from ground level.

In comparison, GRP roofing also appears quite simplistic but creates a professional and clean-looking finish that is entirely seamless. Additionally, fibreglass roofing is available in various colours, offering more options to suit individual aesthetics.


EPDM roofing is considered eco-friendly as it is crafted from recycled rubber. Its long lifespan reduces the need for frequent material replacements, and it can be integrated into green roofs, supporting vegetation and wildlife.

Moreover, EPDM rubber does not pollute rainwater, making it suitable for rainwater harvesting—an excellent method for sustainable living. EPDM's low smog impact and compatibility with solar panels further enhance its environmental profile.

GRP roofing also presents a positive environmental profile, requiring less energy during production compared to other roofing materials. It emits no harmful substances and can be utilised in greywater systems, making it safe for recycling. GRP is also highly durable, reducing the need for constant replacements and minimising environmental impact. Furthermore, GRP can be employed to create green roofs, supporting vegetation and wildlife, and at the end of its lifespan, it can be broken down into composite materials for recycling.

Sustainability - Is GRP better than EPDM?

Is Traditional Felt Still Used?

In the realm of roofing materials, traditional options like built-up felt systems, including torch-on felt and pour-and-roll systems, have long been staples in the industry. These familiar methods have been widely used on rooftops worldwide, primarily due to their affordability and the trade's longstanding tradition.

However, as the roofing landscape evolves, many roofers and experienced DIYers are turning away from layered felt systems and embracing more modern and durable alternatives like EPDM rubber roofing and GRP (glass-reinforced plastic).

Is Traditional Felt Still Used?

One of the main criticisms of traditional felt roofing is its comparatively shorter lifespan when compared to EPDM and GRP. EPDM rubber and GRP boast longer-lasting properties, offering improved durability and longevity, making them more appealing choices for those seeking sustainable roofing solutions.

Another drawback of felt roofing is its proneness to weather damage, particularly during harsh conditions. In contrast, EPDM and GRP roofing systems demonstrate excellent weather resistance, ensuring the roof remains watertight and protected against the elements.

Furthermore, traditional felt roofing may not be ideal for areas with high footfall, especially during the hot summer months. The heat can make the bitumen felt more susceptible to damage, causing blistering and compromising the roof's integrity. On the other hand, EPDM rubber and GRP roofing offer greater resistance to foot traffic, making them well-suited for more accessible or frequently-used areas.

As roofing technology progresses, the popularity of EPDM rubber and GRP continues to grow due to their numerous benefits.

One of the most significant advantages of these materials is their installation process, which minimises hazards and simplifies the roofing project. Unlike traditional felt systems that involve naked flames and extremely hot bitumen, EPDM rubber and GRP roofing systems are safer to install, reducing the risk of accidents and injuries.

While both EPDM rubber and fibreglass roofing require appropriate expertise and care during installation, they are known for being less hazardous compared to traditional methods.

In conclusion, while built-up felt systems still have their place in the roofing industry, many professionals and DIY enthusiasts are embracing the advantages of EPDM rubber and GRP roofing solutions.

These modern materials offer enhanced durability, weather resistance, and ease of installation, making them attractive choices for those seeking long-lasting and safer flat roofing options.

Are you looking for a GRP Fibreglass Roofing specialist in Andover, Basingstoke or Winchester? Our company provides GRP Fibreglass Roofing installations throughout Andover, Basingstoke and Winchester.

Don't hesitate to contact Flat Roofers Basingstoke today! We have staff on hand to answer any questions you might have.