Is EPDM rubber roofing better than felt roofing?

This blog will evaluate many of the factors that determine whether EPDM rubber roofing or felt roofing is the better system. We will first explain what both EPDM and felt roofing are before then evaluating some of the different features of the systems.

We will compare the following topics; Installation process, eco-friendly properties, life expectancy, durability, cost effectiveness, versatility, DIY friendly features and repairability.

What is EPDM rubber?

EPDM is a synthetic rubber that stands for Ethylene Propylene Diene Monomer that has many possible uses from a large scale flat roof to garden sheds and much more.

EPDM rubber roofing is increasingly popular due to its flexibility and excellent watertight properties that make it a great roofing solution.

As it is an impermeable membrane it can be used as a waterproof layer below a green roof system and can be used as a walk-way or a balcony base material.

You can also find out more about what EPDM rubber roofing is and its many benefits in our Benefits of EPDM rubber roofing blog.

Why is it called single ply roofing?

Single ply roofing quite simply means roofing applied in a single layer. EPDM is a great example of an effective single ply roofing system as it creates a waterproof covering in a single sheet application.

This is one of the many advantages that EPDM has, especially in comparison to felt roofing which is a built up system. Other examples of single ply roofing include PVC roofing, TPO and TPE.

What is felt roofing?

Felt roofing is a roofing system comprised of modified bitumen felt which is a combination of asphalt and fibres. The new modified bitumen has evolved from an old roofing method known as built-up roofing. Built-up roofing is achieved by applying multiple layers of asphalt between ply sheets to create a watertight layer.

Felt roofing is commonly known under many different names including; modified bitumen, bitumen roofing, bitumen felt, mineral felt, asphalt flat roofing, bitumen sheet roofing and torch on felt. The name torch on felt comes from the installation process which involves the use of a flame torch to heat the felt so that it will adhere to the roof deck.

What is an example of a built-up roof?

Built-up roofing essentially means a roofing system created from multiple layers. Torch on felt is a great example of a built-up roof as it is commonly installed in multiple layers to increase its durability. The layers often include fibreglass to increase the strength of the whole system.

Torch on roofing can be used as a single ply roofing application, however this isn’t advised as bitumen felt as a single layer doesn’t provide durability.

Is bitumen felt still used in flat roofing?

Yes, bitumen roof felt is still used by many contractors today. Felt roofing that was installed many years ago will likely be suffering from weathering as it is a brittle product that can easily tear and rip. This can cause severe issues such as damage from damp and leaks. Replacing roof felt is often complex and costly as it can only be repaired by a trained installer.

Although felt roofing is still used by many contractors, alternative roofing membranes with easier installation and longer life expectancies such as EPDM are becoming increasingly popular.

Which is better EPDM or felt?

There are many different factors in determining whether EPDM or mineral felt is better.

Throughout the blog we will cover the following areas and answer these questions.

• Installation Process - Is EPDM or felt easier to install?
• Eco-Friendly - Is EPDM or felt more environmentally friendly?
• Life expectancy - Does felt roofing or EPDM rubber have a longer life expectancy?
• Durability - What is more durable, felt roofing or EPDM rubber?
• Cost - Is felt or EPDM more cost effective?
• Versatility - Which is more versatile, felt or EPDM?
• DIY friendly - Is felt or EPDM better for a DIY project?
• Repairability - Is felt or EPDM easier to repair?

Installation process

How easy a roofing system is to install can affect many other elements such as how much it will cost and whether it is DIY friendly or not. So let's compare how easy the installation processes are for both felt roofing and EPDM rubber roofing.

Is EPDM or felt easier to install?

EPDM and bitumen felt differ in how they are installed. EPDM rubber is primarily a cold-applied roofing membrane, which basically means that no heat or naked flames are required to install this system. Felt roofing, however, is a torch down system which means a naked flame is used in order to adhere the modified bitumen sheets together and to the roof deck. One of the reasons why EPDM is considered much easier and safer to install compared to the felt roofing torch on method is because it does not require a dangerous naked flame to complete a successful installation.

Another comparison between the two systems is that EPDM is a single ply system, whilst torch on roofing felt is generally a built up system. A single ply EPDM membrane is generally deemed easier to install as it takes less time for an installer to create an impermeable membrane than it does for a felt roof installer who has to install multiple layers before it is watertight.

Eco-Friendly

It has been clear to see over the past few years that the construction industry is taking steps towards a greener future and avoiding harmful products from being used. This is why it is so important for us to explore which roofing system is more environmentally friendly.

Is EPDM or felt more environmentally friendly? 

EPDM rubber roofing is considered one of the most sustainable roofing systems on the market. This is because most of the EPDM membranes are manufactured from rubber which is fully recyclable. In contrast to this, flat roof felt is made from bitumen that is procured from crude oil which is considered hazardous and therefore less recyclable than EPDM.

Not only is EPDM recyclable, it is a non toxic product that will not pollute rainwater which also gives the option for harvesting rainwater; A popular way of reducing water consumption. The non toxic nature of EPDM also makes it a perfect waterproofing layer below a green roof. In contrast, torch on felt can sometimes leech harmful oils into the environment. Therefore, EPDM is definitely a superior product in terms of environmental benefits.

Life expectancy

When choosing what roofing system to use on a flat roof it is, of course, crucial to understand what will give the best longevity and durability and will stand the test of time. So let's dive into the expected lifespans below.

Does felt roofing or EPDM rubber have a longer life expectancy? 

EPDM rubber has a very impressive life expectancy of over 50 years! Even some of the most basic of the systems on the market offer warranties in the region of 20 to 35 years with some having BBA certificates of up to 35 years available. EPDM far outlasts the older and most basic felt roofing systems that have a shorter life expectancy of between 10-15 years. More recently there have been advances in the manufacturing of felt roofing which has meant that the best roofing felt on the market has an improved life expectancy of up to 30 years.

Despite some recent enhancement in the felt roofing sector, EPDM rubber is still expected to have a longer life expectancy than torch on roofing.

Durability

No roofer wants to return to a job a few years on to hear that the installed system has failed. This is why it is so important to know that the product you’re using is going to withstand weathering and the effects of time. So how do modified bitumen roof felt and rubber roofing perform over time?

What is more durable, felt roofing or EPDM rubber?

EPDM is a flexible, UV and temperature resistant roofing material, making it a fantastic flat roofing solution for durability. It can withstand extreme temperatures and UV rays and its flexible nature means it won’t crack or split with weathering. You can read more about this in our Benefits of EPDM blog. Bitumen roof felt is a dense and somewhat flexible product that is weather resistant, however it can become brittle over time making it susceptible to damage from leaks.

Although bitumen roof felt is a hardy product that will waterproof your roof, EPDM outperforms in durability over time.

Cost-effective

Cost is arguably one of the most important and complex parts of choosing a roofing system. Nobody wants to be out of pocket but it's also important to understand how a system will perform over time to determine how cost effective it really is. A cheaper upfront cost doesn’t always mean it will be cheaper over time. So how do we determine what product to use?

Is felt or EPDM more cost effective? 

There are a few elements to discuss to determine how cost effective each product is. Firstly is the most obvious element which is how much each roofing membrane costs. Although cost depends on each individual project, EPDM is generally a slightly more expensive product to buy outright. Bitumen felt is often seen as a cheaper product between the two, however it is important to look at the full picture.

With EPDM it is easy to install and both a trained professional and DIY enthusiast can install this product which means that there is potential to reduce costs in the installation process. In contrast, felt roofing requires a qualified installer and takes longer to install due to the multiple layer application. This will add up in labour costs making the roofing felt cost more to install.

Another area to consider is durability and life expectancy which we have previously discussed. As EPDM is expected to last longer and is more durable, it is likely to cost less across the years and you are less likely to need a replacement fitting. This makes EPDM the preferred roof covering for cost effectiveness.

Versatility

The versatility of a roof covering can mean many things including its adaptability to different projects and how versatile it is in application. Having versatility means you can install a tried and trusted membrane to your installations. So how versatile is EPDM and felt roofing?

Which is more versatile, felt or EPDM? 

EPDM rubber is an impressively versatile roofing solution and can be used in many different applications. All of our EPDM roof membranes can be used below a green roof, granted they have been correctly installed. Some rubber roofing membranes such as RESITRIX can also be used for overlaying existing roofing systems. Some heavy duty roofing felt can be used below a green roof, however most torch on roofing felt will have joins that are not strong enough to protect against root penetration. Torch on felt is also less commonly used in overlay systems due to the bitumen felt welding involved.

EPDM is also versatile in its application process as it can be supplied in both rolls and in a large single sheet cut to exact measurements. Bitumen sheet roofing, on the other hand, is limited to roll application only.

It is easy to see that EPDM is a more versatile roofing solution than torch on roofing.

DIY friendly

With costs ever rising and working from home now becoming quite popular, there is an increase in people installing their own garden rooms and undertaking DIY roofing. So are these roof coverings DIY friendly?

Is felt or EPDM better for a DIY project?

Rubber is a DIY friendly system that can be applied without the need of an experienced tradesman. With its simple single ply design and many online step by step guides and videos available, EPDM is a great option for the DIY roofer. We even supply shed roof kits which come with the exact amount of product required for the job! It is common to see shed roof felt on the market, however it is essential that shed felt should be installed by a skilled tradesman especially with the use of a naked flame.

Felt roofing is, therefore, not the preferred system for a DIY project and EPDM would be best suited for the DIY enthusiast.

Repairability

Nobody plans for a leaking roof but should damage occur it is always best to know how easily and cost effectively you will be able to repair the damage. So if damage does occur which system is going to be easier to repair?

Is felt or EPDM easier to repair?

Rubber roofing repair is reasonably easy should damage occur. If there is a split or puncture in the membrane then a brand specific patch can be adhered at very little cost. Repairing roof felt is more difficult and it is essential to have a felt roof specialist take on the repairs to ensure it is done correctly and safely. The cost to refelt a roof is often expensive due to the tools and labour required.

Therefore EPDM is a much easier system to repair than a bitumen felt roof. If you are in the process of replacing roof felt, it is worth considering EPDM as a roofing felt alternative.

So which of these really is the best option?

Considering all of the benefits that EPDM rubber roofing has, it is clear to see it has become a superior product to the traditional felt roofing. At the end of the day, a mineral felt roof will do the job but EPDM will outperform and give you the best bang for your buck throughout its life span. So what are you waiting for? Order your EPDM now and reap the many benefits it has to offer.