Everything About EPDM Roofing

Last updated: 04 Apr 2023

If you’re in the market for a new flat roof, here’s everything you need to know about EPDM and how It all works.

Everything About EPDM Roofing

The great British weather seems to be getting more extreme, and if it’s not a heat wave through the summer, it’s sub-zero temperatures and frosts through the winter.

Pitched roofs with slates or tiles cope fairly well with extremes of temperature, although they can be affected by high winds.

Flat roofs on the other hand sometimes do not stand up as well to winter and summer temperatures, and this is something to bear in mind if you have a flat roof already, or are thinking of installing one.

Felt Roofs

Many of the flat roofs on homes in the UK are still made of felt. Felt is cheap to buy and install, and has to be put onto the roof with melted on tar. Felt isn’t particularly good at standing up to extremes of temperature though, especially as it gets older.

The average flat roof covered in felt only lasts for 20 years, and if your flat roof is 10 years or more old, it is much more likely to develop cracks and splits in bad weather. The first you’ll know of damage to the roof is when you spot a leak underneath, so regular inspection of your flat roof is essential throughout the year.

If you spot any blistering, cracks, breaks or splits, call in a roofer right away to replace the whole roof or the damaged section.

The average cost for replacing a three layer felt flat roof, including all the flashings, labour and materials stands at about £1000.

EPDM as An Alternative To Felt

Although felt is prone to developing problems in extreme weather, there are some new roofing products on the market which are much more weather resistant.

EPDM is a plastic type roofing material which is much smoother to the touch than felt, and which is also much more durable.

EPDM is very popular in the USA, where it is well accustomed to the hot weather of Texas and Florida as well as the chilly temperatures of an Alaskan winter.

EPDM is more expensive to install than a felt roof at around £1,500, but the longer lifespan and the durability of the product might mean that in the long run it is a better investment.

Fibreglass versus EPDM

Fibreglass is gaining in popularity as a roofing material, mainly because of its durability and the fact that it can be coloured in a number of different shades.

The costs for installing fibreglass are about the same as for EPDM, and it is also very lightweight and easy to install on the roof.

Fibreglass roofs can be painted to prolong their lives, and due to the way it is manufactured in sheets, it is less likely to leak than smaller pieces of felt, which are prone to leaking along the joins.

Given that both fibreglass and EPDM are relative newcomers to the world of flat roofing, the problem for the homeowner is often finding a roofer who is experienced in installing this sort of roof and can do the work at a reasonable price.

EPDM Explored

Thinking about replacing a flat roof? In the past, this style of roof has had a bad reputation – prone to leaks and with a relatively short lifespan. This is because flat roofs have until recently been made using rolls of felt, which were attached onto the framework with asphalt. However, the flat roof market has been revolutionised by a new material called EPDM. If you’re in the market for a new flat roof, here’s everything you need to know about EPDM and how It all works.

What exactly is EPDM and why is it different?

Traditionally, flat roofs have been covered in felt and the joints sealed with bitumen. Although at first the surface is waterproof and solid, over time the felt starts to break down. Eventually even the most professionally applied felt flat roof will start to leak.

It’s estimated that the average lifespan of a felt flat roof is about 20 years. EPDM, or ethylene propylene diene monomer to give it the proper name, is a synthetic rubber product.

EPDM has in recent years become the default choice for flat roofs. If you’re a parent you’ll be familiar with the other common use of EPDM, which in its granular form is used to provide soft surfaces in outdoor play areas.

On the roof, EPDM is a softer, more flexible product than felt. EPDM also doesn’t need bitumen to seal it either. Manufacturers will guarantee an EPDM roof for around 25 years. Most experts estimate EPDM roofs will last longer than that.

What is EPDM Made From?

EPDM stands for ethylene propylene diene monomer. It’s a long and complicated name for what is a synthetic rubber product. EPDM is made in the lab and has a number of applications apart from roofs. You’ll find it in other products such as seals around the windows in your car, pond liners, electrical insulation and garden hoses. EPDM is also used to make brightly coloured playground surfaces. Just like rubber, EPDM is flexible and can be bent and twisted into any shape.

Advantages of EPDM

The main advantage of EPDM is that is easier to fit to the roof than traditional felt. It is available in wider rolls, and for a smaller roof, it’s often possible to fit it without any joins at all. As joins are often the weak spot where water can start to get into the roof, this is good news for homeowners. Unlike traditional felt which uses blowtorches and heat to fix the felt onto the roof, EPDM is stuck down with special adhesive. EPDM is available in black or white, and gives a smooth and contemporary look to any home.

Maintaining and Repairing EPDM Roofing

EPDM roofing requires very little in the way of maintenance. Stones should be swept off and any moss washed off with washing up liquid and warm water. If there is a problem with EPDM, it can often be patched rather than replaced. It’s best to get the professionals in to do the job though, especially if your roof is still under guarantee.

Lifespan of EPDM Roofing

The average lifespan of a properly fitted EPDM roof is between 20 and 30 years. This is twice as long as a felt roof, which can be expected to last around 10 years on average. EPDM is a relative newcomer in the roofing market, and as techniques for manufacturing and fitting improve, we’re likely to see this lifespan stretch longer.

Many homes in the UK have a roof which is either completely flat and partially flat, and although this form of roofing has been popular over the last decades, it’s not without its drawbacks.

Flat roofs are made in a completely different way from traditional pitched roofs with tiles or slates, and are more prone to leaking.

That’s why you’ll find a question about the percentage of your roofing area which is flat when you renew your buildings insurance.

In fact, people who live a house where the flat roof area is more than 40% of the total might struggle to find standard insurance cover.

It looks like insurance companies are going to have to completely change their way of quoting though, as new technology is completely revolutionising the flat roof market.

Benefits of EPDM Roofs

One of the major advantages of EPDM as an alternative to felt or bitumen is its increased lifespan. There are several other advantages to using EPDM roofing.

As the material is more flexible, it is easier to use on roof spaces which are uneven or which have skylights or other windows. It doesn’t break down in sunlight, and is resistant to the most extreme weather conditions. EPDM does not need to be applied to the roof with heat as felt does, so it is safer to install.

Manufacturers make EPDM sheets big enough to cover an area of up to 50 square metres in a single sheet. This cuts out the need for joining sheets completely and lessens the chances of leaks. It can also be a more cost-effective choice than felt for your flat roof.

Costs of EPDM Roofs

One criticism levelled at EPDM roofs is that they are more expensive than felt flat roofs, and if you look at the price of the material on a per metre squared basis, that is probably true.

When you are talking to roofers about the cost for replacing your roof they will calculate their costs depending on the size of the roofing area, taking into account their labour, materials and other costs such as scaffolding.

You can expect to pay around £80 per square metre for an EPDM roof, compared with £50 for a felt roof. This may seem like a big difference in price, but it’s also important to factor in how long you expect the roof to last.

Spending more initially on an EPDM roof might mean you get a product which lasts twice as long as felt, and doesn’t need repairing when it starts to degrade.

In the long run, investing in a new EPDM roof rather than simply replacing a felt one with more of the same is well worth the money.

Can all roofers use EPDM?

EPDM has become very popular in recent years and it’s therefore unlikely that you’ll come across a roofing firm which does not know how to use this product.

Some may refer to it as a brand name like RubberCover or RubberGuard, which are brands used by the manufacturer of EPDM, Firestone.

When you are asking local firms to quote for replacing an existing flat roof with a new EPDM covering, always check that they have completed similar projects in the past.

A good roofing firm will not hesitate to give you references and be happy to talk about similar jobs they have done in the past.

Use this information beside other variables such as price and reputation to help you compare the quotes and decide which one offers the best value for money.

Remember – always get at least three quotes from roofers in writing, and never agree to pay anyone the full amount for the job up front.

Ask friends or family to recommend roofers who they have worked with successfully in the past.

You can also check out the local listings on Top Tradespeople to help you draw up a shortlist of companies to approach for a quote.

How Long Will it take to Fit My New Roof?

The length of the job will depend on how much preparation work the roofing firm has to do first before they can get started.

If your roof is difficult to access, they might have to put up scaffolding first.

If the battens and beams supporting your roof also need to be replaced this work will have to be done first, and it will also add considerably to the cost.

Ask your roofer for a breakdown of the project when quoting so that you have realistic expectations about how long things are likely to take.

It’s also usually better to try to plan roof replacement work for the summer months when the hours of daylight are longer and the roofers can work longer hours each day.

If you only have a small section of flat roof, such as on a single storey extension, the job can be done in a day.

Replacing the roof on an entire three bedroom house will take about a week, and if your job means replacing roofing beams and joists, it could take as long as three weeks.