What Materials Do You Need For A Flat Roof?

Choosing the right flat roofing materials can make all the difference when it comes to protecting your property from the elements. Whether you’re replacing an old system or starting from scratch, understanding the different types of flat roof materials, their benefits, and how they handle weather conditions is key to making the best decision.

Flat roofs may look simple compared to pitched roofs, but when it comes to choosing the right roofing material, there’s plenty to think about. From EPDM rubber roofing to torch on felt, every system has its pros and cons depending on your budget, building type, and how long you want the roof to last.

This guide breaks down the best flat roof materials available, how they work, and what makes each roofing system stand out.

What Is a Flat Roof?

A flat roof is exactly what it sounds like. A roofing style that appears flat, but actually has a very slight pitch to allow water drainage. They’re commonly used on extensions, garages, commercial buildings, and even some modern homes.

Flat roofs tend to be more affordable than pitched ones and easier to access for maintenance. But to get the most out of them, choosing the right materials is crucial.

What Makes a Good Flat Roofing Material?

Before we go into specific options, it’s worth looking at what makes a roofing membrane suitable for flat applications. A good flat roof system should be:

• Water-resistant or waterproof
• Durable in all weather conditions
• UV-resistant to withstand sun damage
• Long lasting, ideally up to 50 years
• Cost effective for the size of the roof
• Easy to install, especially in hard-to-reach areas
• Capable of resisting cracks, punctures or shrinkage

Some systems are better suited to foot traffic, while others are designed more for insulation or longevity. With that in mind, here are the main types of flat roof materials used today.

EPDM Roofing (Rubber Roofing)

EPDM roofing (short for ethylene propylene diene monomer) is a type of synthetic rubber roofing membrane widely used across the UK. It’s known for being strong, flexible, and very long lasting. Many systems last upwards of 40 to 50 years with proper installation.

Key Features:

• Comes in large single sheets
• Suitable for most roof shapes
• Resistant to UV rays, wind and rain
• Requires minimal maintenance
• Easy to repair with adhesive patches

Because EPDM rubber roofing is lightweight and easy to install, it’s often a popular choice for both residential and commercial projects. It’s a particularly cost effective option for larger roof areas.

One important note: EPDM is black, which means it can absorb heat. For roofs that get a lot of sun, it’s worth considering insulation underneath to improve performance.

GRP Roofing (Fibreglass)

GRP roofing, or glass reinforced plastic, is a solid, heavy duty option often used on domestic properties, garages, and extensions. It’s made using layers of fibreglass matting and resin, which cure to form a seamless, joint-free surface.

Key Features:

• Seamless, waterproof finish
• Strong and rigid surface
• Very low maintenance
• Clean, modern appearance
• Resistant to UV rays, cracks and splitting

Fibreglass roofing is well known for its neat finish and durability. The GRP fibreglass surface is completely watertight and performs well in tough weather conditions. It can also be walked on, which is handy for roofs with occasional foot traffic.

Installation does require a dry day and some skill to get the resin mix right, so it’s not ideal for DIY. But if done correctly, it can last for decades with little to no issues.

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Roofing Felt (Torch On Felt)

Roofing felt, particularly torch on felt, is a traditional roofing material that’s still widely used for flat roofs in the UK. It’s made by laying bitumen-coated felt sheets in layers, which are bonded together using a gas torch.

Key Features:

• Multi-layered protection
• Inexpensive and widely available
• Works well on small or awkward roofs
• Suitable for garages, sheds, and outhouses
• Easy to repair if damaged

Felt roofs have improved a lot over the years and now come with added strength and weatherproofing. While not as long lasting as other options (around 10–20 years), they’re still a reliable choice for lower-budget projects or temporary structures.

Torch on felt requires heat for application, so always use a qualified installer to ensure safety and a proper seal.

Single Ply Membranes

Single ply roofing systems use a single layer of durable synthetic material, often PVC or TPO, to form a waterproof layer. These systems are common in commercial builds but are becoming more popular on modern homes.

Key Features:

• Lightweight and flexible
• Heat-welded seams for full waterproofing
• Good thermal performance
• Quick to install
• Resistant to chemicals and pollutants

Because single ply systems come in large rolls, they can cover big areas with fewer joins, reducing the risk of leaks. They’re also UV-stable and have a smart, smooth finish.

They’re best suited to larger, newer buildings where insulation and environmental performance are a priority.

Modified Bitumen

Modified bitumen is a close cousin of felt but offers added strength and flexibility. It’s made from bitumen (a sticky, tar-like substance) reinforced with polymers. It’s usually installed in layers with adhesives or torch application.

Key Features:

• Multiple layers add protection
• Good resistance to foot traffic
• Reasonably priced
• Can be used with insulation boards
• Performs well in harsh weather conditions

Modified bitumen is still one of the go-to choices for roofers who want a time-tested material that’s tough and adaptable.

Recycled Rubber and Eco-Friendly Options

For those looking to reduce their environmental impact, rubber roofing made from recycled materials is an increasingly popular option. Some EPDM roofing membranes, for example, are made from recycled tyres and industrial rubber waste.

Similarly, recycled roofing felt, green roofs and eco-friendly insulation boards are now available on the market, giving homeowners and contractors greener options without compromising on quality or performance.

What’s the Best Flat Roof Material?

The best flat roof system for you depends on your building type, budget, and how long you want it to last.

Material	Lifespan (approx.)	Cost	Ideal For
EPDM Rubber	40–50 years	Moderate	Homes, extensions, commercial roofs
GRP Fibreglass	25–40 years	Moderate-High	Modern homes, garages, walkways
Torch On Felt	10–20 years	Low	Garages, sheds, temporary structures
Single Ply	25–40 years	Moderate	Larger buildings, energy-efficient homes
Modified Bitumen	15–30 years	Moderate	Domestic and commercial applications

Flat Roof Accessories and Installation Materials

Besides the main roofing membrane, a flat roof build or replacement may require:

• Adhesives: Used to bond the membrane to the decking or insulation
• Insulation boards: Help improve thermal efficiency
• Edge trims and fascias: For clean edges and waterproofing
• Underlay: Adds extra protection in multi-layer systems
• Primers and sealants: Prepare and finish surfaces

Working with a qualified roofer ensures the right materials are used for your specific roof type and that everything is installed to manufacturer specifications.

Repair and Maintenance

All flat roofing materials will eventually need repairs due to weather, impact, or age. Choosing a system that’s easy to repair can save you time and money down the line. EPDM and roofing felt tend to be the easiest to patch up with adhesive kits or sealant.

Regular inspections, especially after heavy rain or wind, can help spot early signs of damage such a roof leak, before it becomes a bigger issue.

Final Thoughts

If you’re unsure which roofing system will work best for your property, we’re here to help. At C Kearney Roofing, we supply and install all major types of flat roofing, always using heavy duty, proven materials designed to last.

We’ll guide you through the pros and cons of each roofing material, explain your options, and tailor the solution to your budget, usage needs and location.

Get in touch with our team today to talk through your project or request a quote. With quality materials and expert installation, your flat roof will be in safe hands for years to come.

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