What is EPDM Rubber? Everything you need to know

Whether you’re repairing a garage, re-roofing an extension, or creating a new green roof, choosing the right flat roofing material is essential. You need something that’s reliable, long-lasting, and ideally easy to install yourself.

That’s where EPDM rubber roofing comes in.

In this guide, we’ll break down exactly what EPDM is, what it’s used for, how it compares to other materials like felt and GRP, and whether it’s the right fit for your project.

What is EPDM rubber?

EPDM rubber (ethylene propylene diene monomer) is a highly versatile synthetic rubber used for flat and low-slope roofing projects. EPDM has a lifespan up to 50 years; it’s ideal for both commercial and domestic use as it’s incredibly durable, flexible and lightweight, making it one of the best systems for flat roof projects. 

It can be used for a variety of applications including:

• Flat roofs
• Green roofs
• Felt roof replacements
• Garage roofs
• Low-pitch roofs
• Shed roofs

How long does EPDM last?

EPDM rubber is one of the most reliable and long-lasting systems out there, with a life expectancy of at least 50 years. EPDM is designed for use in the coldest to the hottest temperatures, remaining flexible and stable from -45°C up to +120°C, which makes it resistant to cracking caused by temperature changes. 

Compared to other flat roofing systems, EPDM has the best life expectancy.

• EPDM: Up to 50 years
• GRP: 10 - 25 years
• Felt: 10 - 15 years

Which is better for my roof - EPDM or GRP?

The answer to this question depends entirely on whether you have a simple or more complex roof.

When is EPDM better?

EPDM is ideal for simple roof layouts, like sheds, garages or extensions, with no or one skylight. This is because you can lay the membrane down without needing to make many alterations.

Additionally, because EPDM is an impermeable membrane, it can be used as a waterproof layer below a green roof system. This is because it handles constant moisture much better than GRP systems do.

When is GRP better?

GRP roofing is a liquid-based system that’s ideal for complex roof layouts, like roofs with multiple skylights, pipes, or corners, as it can be moulded and shaped around awkward details. 

The biggest downside of GRP is that it doesn’t do well in damp conditions, and any imperfections to the surface can cause leakages.

Is there a middle ground between EPDM and GRP?

If you’re working on a more complex roof but still want the flexibility and reliability of rubber, RESITRIX offers a strong middle ground between EPDM and GRP.

RESITRIX is a rubber-based membrane that’s heat-welded rather than glued. This gives it the flexibility of EPDM, allowing it to expand and contract with the building, while also providing the strong, permanently bonded seams you’d expect from EPDM, GRP or liquid systems.

Because it can be welded around skylights, pipes, corners, and vertical surfaces, RESITRIX is well-suited for complex roof shapes—something that standard EPDM struggles with.

Which is better for my roof - EPDM or Felt?

Unlike GRP, the comparison between EPDM and felt is much more clear-cut. EPDM rubber is a far superior product to traditional felt roofing, and these are just some of the reasons why:
 

• Material: Felt roofs tend to crack under long-term sun exposure or experience water ingress in freezing temperatures; overall, felt roofing has a life expectancy of 10-15 years. EPDM is better as it’s designed to easily handle extreme temperatures, remaining durable & flexible all year round; overall EPDM has a lifespan up to 50 years.
   
• Installation: Felt roofs often require a heat torch to install and often need refelting completely during repairs. EPDM is better as it’s easier to install and can be done so using simple tools; repairing is also much easier as it can be done in patches. 
   
• Application: Felt is applied in smaller rolls, increasing the amount of seams which increases the likelihood of water getting in. On the other hand, EPDM is sold as large, single sheets, which you cut down to your desired size. This reduces the amount of seams, and gives you a much more watertight finish. 
   
• Costs: In the short run, felt will work out cheaper and can be a good option if you have a tight budget or are working on a very small project. On the other hand, whilst EPDM is more expensive upfront, it makes up for it in the long run. Ultimately, you’re paying for quality, and with a lifespan of more than double that of felt, plus much easier maintenance and repair, it’s the better choice. 
   

Overall, EPDM is better than felt - read our EPDM vs felt blog, which dives deeper into these reasons. 
 

How much does EPDM rubber cost?

The cost of EPDM rubber varies between brand and thickness, however, you should expect to pay anywhere between £8 - £12 per m². 

Unsure what you need? Our ClassicBond calculator ensures you’re sent with the exact right amount of materials you’ll need for your project.
 

Is EPDM rubber roofing easy to install?

EPDM rubber roofing is easy to install for both DIYer’s and professional roofers on multiple applications. It can be supplied in large, single fit sheets up to 450sq.m or smaller - simply cut down to your required size and install. 

Watch our installation guide below for more information and a step-by-step walkthrough.
 

How do you maintain EPDM rubber?

EPDM rubber roofs are incredibly low-maintenance, but there are a few things you can do to ensure the best quality possible. 

• Clean it twice a year with a brush, sweeping off leaves, dirt and debris
• Check it after periods of heavy rain or storms. If you spot any punctures in the membrane, you can repair it before it causes more damage. Our EPDM rubber roof repair kit is a great choice, coming with everything you need to resolve the damage. 

Associated problems with EPDM and how to overcome them

Shrinkage

Like all rubber, EPDM membrane can be subject to slight shrinkage. This typically happens because the membrane has been overstretched. Instead, it should be laid flat and relaxed before installation. Large roofs over 100sq.m need reinforcement strips (RUSS Tape) to manage shrinkage over time. It is also very important to ensure the correct amount of contact adhesive is used around the edges during installation.

Rips, tears & leakages

Whilst EPDM rubber membrane is highly durable, it can be subject to punctures from sharp tools or stones; as a result, your roof will be exposed to the elements and subject to leaks. As stated previously, the best way to avoid leak damage is to repair the membrane as soon as possible - using an EPDM repair kit is a great way to do this. 

Poor installation

Incorrectly installing EPDM rubber often results in bubbles, folds, and poorly sealed seams or gaps around the edges. This can lead to leaks and water damage to the decking below. 

It sounds simple and obvious, but the best way to ensure proper installation is to follow manufacturer instructions - we strongly recommend hiring a professional if you lack experience installing EPDM systems or aren’t comfortable with DIY tasks.

If you’re a DIYer and want to make sure your project goes ahead without any hiccups, check out our EPDM kit builder. We put these together to your exact specification, ensuring you have the required amounts of everything needed to complete the project.

Is EPDM rubber the right choice for my roof?

If you’re working with a simple flat roof—like a garage, extension, dormer, or outbuilding—EPDM is one of the best choices you can make. It’s flexible, durable, cost-effective, and easy to install, making it ideal for both professionals and confident DIYers.

While it's not always the best fit for more complex roofs with lots of skylights, vents, or awkward detailing, it outperforms traditional felt in every way, offering a low-maintenance, long-lasting solution for up to 50 years.

If your roof is relatively straightforward and you want something that just works without causing you many headaches, EPDM rubber is likely the right call.