Reduce – Reuse– Recycle… How does EPDM score?

What makes a roof sustainable? First of all, it’s about using the least amount of resources. Secondly, it’s a matter of durability: the longer it lasts, the better. Finally, it should be made of a material that can be reused or recycled. 

In general, roofing membranes have the highest environmental impact (expressed in GWP -Global Warming Potential or equivalent CO₂) at the time of their production and disposal. This means that the premature failure of a roof constitutes nothing short of an environmental disaster, especially when taking into account hidden environmental costs such as the additional manufacturing, labor, shipping, tear-off and related energy costs needed to replace a roofing system. However, if the durability of a roof is significant and can be further enhanced through repairs, its overall impact on the environment is drastically reduced. There is no doubt that choosing a durable roofing system is an important part of the designing process for anyone who wants to be environmentally responsible. EPDM roofing membranes are a solution that checks all the boxes of environmentally responsible, circular construction.

EPDM (Ethylene-Propylene-Diene Terpolymer) roofing membranes are 100% vulcanized membranes made of a synthetic rubber Ethylene-Propylene-Diene Terpolymer. They were first introduced in the roofing industry in the 1960s and have since been used around the world in all types of climates. The production of EPDM membranes has a low embodied energy number (i.e. the amount of energy required to produce and implement a product from material extraction, manufacture and installation). 

Studies prove that when it comes to the use stage, EPDM roofing membranes show exceptional durability compared to other roofing materials (see e.g. the "Evaluation of the useful life of EPDM roofing membranes” study by the German Süddeutsche Kunststoff-Zentrum). With a life expectancy of over 50 years, EPDM roofing membranes remain stable and unchanged over time,  also thanks to their high resistance to ozone, UV radiation, microorganisms and severe weather conditions such as hail. 

Another important factor is the outstanding elasticity of EPDM membranes. Even in  extreme temperature fluctuations, they easily expand and contract, thereby accommodating to the potential building movements. That is why EPDM membranes can be used in a variety of climates, from the sub-zero temperatures of Alaska to the sun-baked landscapes of the Middle East. Last but not least, they do not contain volatile ingredients or products that may migrate or degrade over time, such as plasticizers or antioxidants, so there is no danger of the material becoming brittle or cracking, even after several decades of exposure.

Greenpeace, GreenTeam and the Dutch Institute for Building Biology and Ecology (NIBE), have put forward EPDM roofing membranes as the ones with the lowest environmental impact. NIBE’s assessment, carried out every two years, takes into consideration the initial costs (material and installation costs) as well as all hidden environmental costs (raw material consumption, energy consumption during production, etc.) of different types of roofing membranes. The result of this comparative classification shows that mechanically attached and fully-adhered EPDM roofing membranes have the lowest hidden costs, which makes  them the most environmentally friendly flat roofing choice. 

In addition to their low initial environmental impact and remarkable durability, EPDM roofing membranes are easy to repair, which means their service life can be extended beyond 50 years. They are also very adaptive. Even several decades after the initial installation, changing roof details, adding skylights, roof vents and other roof openings can be done easily without having to remove the membrane. 

Thanks to these attributes, EPDM roofing membranes can play a key role in achieving the highest scores in recognized green building rating systems such as BREEAM® and LEED®. These programs evaluate buildings according to the efficiency with which they use natural resources and their overall impact on human health and the environment. What further enhances the environmental credentials of EPDM is its suitability for application on active roofs: green roofs, solar roofs and water-collecting roofs (also known as “blue roofs”).

At the end of their service life, EPDM roofing membranes can be either reused or recycled. EPDM membranes that have been held in place using ballast (river-washed gravel or pavers) can be simply removed and relocated to another roof. Membranes which have been mechanically attached can also be recovered by removing the fixing elements. 

Another way of reusing end-of-life EPDM roofing membranes is by downcycling. Thanks to their stable composition, they can be grinded into smaller rubber compounds and used for a long list of high added value solutions such as sports tracks, roads or rubber mats for children’s playgrounds and so on. Ingredients such as carbon black can also be extracted from EPDM and can be reused either as fillers in new EPDM membranes or as compounds for different materials. Reusing EPDM membranes helps to reduce the need for virgin raw materials, allowing a more responsible use of natural resources. Such downcycled products are also almost infinitely recyclable.

When reusing or downcycling are not an option, EPDM membranes can be recycled. There are several ways to recycle EPDM, such as chemical and mechanical recycling, pyrolysis, devulcanization, etc. However, recycling should only be considered as the last option before landfilling/incineration, since energy and resource demand for recycling is, in most cases, much higher than producing virgin products.