EPDM

Flat roofing

Ethylene propylene diene terpolymer or as it is much more commonly and easily known EPDM. Not so much of a mouthful! This type of flat roofing is becoming much more popular. The big benefit with EPDM is that is can be manufactured in one sheet. This means there are no joints. Joints in coverings are weak spots.  So, a point of failure. When a complete sheet is used there is a very limited failure rate. Depending on the manufacturer these can have guarantees ranging from 20 years. In the case of Firestone one of the premium manufacturers. They suggest a staggering 50 year life expectancy. This is well beyond any of the flat roofs discussed so far.

Bristol

EPDM, has been popular in America for a long time. The trades are skilled in its use. It has been used for say the last 20 years or so. We first encountered it in 2006 at a London trade show. With popularity in Bristol increasing all the time. Although installers would disagree. It is not ideal to be used when there are lots of penetrations. Such as Velux’s or lantern lights. This is because the main benefit of one sheet is lost. It is still acceptable, but the extra long life spans will be reduced with joins.

Reactive vs proactive

EPDM is being used a lot for repairs. This is where failing flat roofs are simply covered over with a sheet of EDPM. So you cannot always know the substrate. As these have only been used for say the last 15-20 years. We do not really have a good picture as to its life expectancy in the UK, yet.

With EPDM it tends to be the decking that fails first normally related again to the decking onto which it is laid.

The trades perspective

To cover a single flat roof. EPDM – Ethylene propylene diene terpolymer is cost effective and hardy. It is easy to install, only water based adhesive is required. It does get much more awkward, when used on a complex roof. Cutting large sheets is challenging on small sites. Often resulting in smaller upstands and cuts. These can peel off as we show in the picture.