What Should I Know About EDPM Roofing?

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In the US, EDPM is already widespread. In the UK, this is not so – or at least, not yet.EDPM is fast attaining ubiquity in the flat-roofing world; this is largely owing to its durability and its moisture-excluding properties.This reputation is undoubtedly deserved, as this has been proven time and again in both laboratory experiments and in the field.

What is EDPM?

EDPM is a compound of two different sorts of oil – propylene and ethylene.It is formed into sheets which can be used to keep moisture away.These sheets are useful in a number of applications, but mostly they are used on flat rooftops.

Unlike the vast majority of roofing materials, EDPM is uniquely equipped to deal with a huge variety of different climates.While many roofing materials require a great deal of additional treatment to survive the extremes in temperature, EDPM avoids this – and is the only material which does so; it is as at home in Egypt as it is in Antarctica, straight out of the proverbial box.


EDPM has a number of properties which make it especially useful for flat roofs.Though it can also be laid atop other geometric structures, such as dome and barrel-shaped roofs, EDPM is principally used in flat roofs.But when it comes to roofing, the term ‘flat’ can be misleading.A great many roofs which are described as ‘flat’ are not so; they are instead slightly sloped.Why is this the case?The answer lies in the need for drainage.

Problems caused by pooling

A truly flat roof would provide rainwater with little means of escape.Instead, water would become trapped and thereby place stress on the underlying material.The fact that winter is almost here lends this consideration even greater importance – rainwater will not evaporate.

The surface beneath will therefore suffer – but the extent of this will depend on the material used.In the case of felt roofs, drainage is especially important, as pooled water can penetrate the roof below, causing leaks.The underlying supports, which are often made from cheap wood, will suffer accelerated decay should water find its way through the top layer.EDPM guards against this danger; as well as being thoroughly waterproof, it is flexible, which lessens the amount of damage EDPM can cause over time.

EDPM is less prone to this problem.It is not porous and so can withstand far larger quantities of standing water.Provided that the membrane is properly installed, it will be impenetrable which in turn prevents damage to the roof’s underlying structure.

In the same way, EDPM’s resistance to moisture also guards it against seasonal damage.Water can penetrate and enlarge any tiny fissures which might form in the surface of a porous roof, thereby slowly eroding that surface over time.EDPM is also especially resistant to changes in temperature.As well as being less porous, EDPM is less prone than its competitors to changing shape in response to seasonal change.During winter it will retain its flexibility, which is a large part of the reason that it’s so long-lasting.Since its introduction forty or so years ago, estimates as to its lifespan have had to be revised upward.

As well as being very durable, EDPM is also very easy to maintain.

How is EDPM membrane put together?

Many sheet-based roofing solutions are necessarily welded together using a large blowtorch.There are many disadvantages to this method, however, not least of which is the high cost of buying and running this equipment and the labour necessary to operate it.The intensity of the flame makes this method very dangerous as well – and so requiring further expenditure in the form of insurance.

EDPM membrane avoids this method and is instead installed in one of two ways:

Liquid adhesive

We’re talking about glue, here.It is applied along one of the adjoining seams and dries in a few hours.This also removes any tiny gaps through which moisture might be able to penetrate.


Once two sheets of EDPM are placed adjacently, tape is applied to the seam.This method means that the surface of the roof is far smoother, as the sealant can be applied more consistently.

As well as being adhered to a surface, EDPM can be laid down loose, or nailed into place.A thorough explanation, along with advice on how best to proceed, can be provided by any good flat roofing contractor. In Coventry you can find one such company, they can be reached at www.marcusroofing.co.uk.


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