What is an EPDM and what is Prelasti?

AAC Waterproofing - Exclusive Installer of EPDM Prelasti

EPDM or Ethylene Propylene Diene Monomer to call it by it’s full name (I think I’ll stick to EPDM) is a type of synthetic rubber that is usually made from recycled materials.

What is an EPDM?

EPDM Membrane creates an airtight and weathertight seal which is used for a wide variety of applications. Since it was first created EPDM has been built to stand the test of time and its resistance to weather is what sets it apart from other elastomers, making it the system of choice for architects, contractors, and building owners alike.

EPDM is suitable to the flat roofing industry and the relevant roofing projects because if its durability, long lifespan, and it is easy to install.

What is Prelasti?

Here at AAC, we have our own EPDM called Prelasti.  Developed by Pirelli over 30 years ago, Prelasti is a unique made-to-measure, prefabricated rubber roofing membrane. It is fitted in complete safety without hot bitumen or flames and carries a minimum 10-year guarantee.

AAC Waterproofing are an approved installer of Prelasti

The advantages of using Prelasti include:

Speed and security of the rubber roofing system installation

Made-to-measure – The Prelasti Membrane will be produced based on detailed drawings which we make of your roof area.

Prefabricated – The Preasti Membrane will be prefabricated in the factory under ideal conditions.

The rolls of Membrane are cut to length and welded together where necessary to form a single sheet based on our drawing of your roof.

Delivered to the site – The prefabricated sheet of Prelasti Membrane, custom-made to the size and shape of your roof, is folded and packed for delivery to your site ready to install.

Your new Prelasti Roof Covering is installed in a single, guaranteed waterproof sheet, custom-made to the individual requirements of your property. Once the installation is successfully completed, we offer a Full 20 Year Guarantee. Current experience and research leads us to believe that due to exceptional resistance to ageing, 50 years of life expectancy is a realistic expectation.

All season installation

Prelasti roof sheets remain flexible and can be installed without difficulty in all seasons irrespective of most weather conditions.

Temperature variations

The EPDM is not affected by extremes of temperature. It will not soften in high temperatures or embrittle in freezing conditions. The product has been exhaustively tested to withstand temperatures varying from minus 40 degrees to plus 110 degrees Celsius.


Prelasti is highly elastic and will accommodate any stretching imposed on the roof covering by building movement without a problem. Your new roof covering will not tear, crack or split. In fact, it will stretch a massive 400% without causing damage to the Membrane.

Highly puncture resistance

The Prelasti EPDM membrane is highly puncture-resistant – resistant to root penetration and therefore ideal for roof gardens in addition to its main use for simple waterproofing of flat roofs.

Prelasti is also resistant to atmospheric pollutants such as acid rain. It does not degrade under Ultra Violet Light or Ozone attack.

Prelasti Membrane Used on Flat Roof

Safe installation

No fire risk – No flames or hot boilers are used to install a Prelasti roof. There is therefore no fire risk to your premises. The Prelasti Membrane is simple to install and is applied cold.

Some Local Authorities and Companies will no longer allow hot bitumen and felt on their premises for the simple reason of the fire risk alone.

Lightweight – Prelasti is one of the lightest roofing materials available. It is highly suitable for lightweight structures and puts negligible load on roofs to be refurbished.

Prelasti is available in both 1.2mm and 1.5mm thicknesses weighing 1.4 kg per square metre and 1.8 kg per square metre respectively.

Ecologically sound

The Prelasti System is considered to make less impact on the Environment than many of its competitors such as Firestone EPDM.

Less energy is used in its manufacture than with felt and bitumen products coupled with a very low usage of Global Resources.

The Prelasti Membrane is considerably less Toxic than its PVC counterpart and can also be re-used if required by grinding down and using the resultant granulate as a filler.

Comparisons with all other forms of flat roofing product show Prelasti to rank amongst the least damaging to all aspects of the Environment.

Low maintenance

The Prelasti membrane has been subjected to Independent tests performed by the renowned independent German engineer Heinz Gotze.

The engineer took three representative samples at random from Prelasti rubber membranes fitted in 1976. These involved a tyre plant and two different types of education establishment, one of them with a roof that sees children regularly clambering over it.

Sections were cut away, examined in detail on site and then taken to laboratories for microscopic tests. The lab tests included looking at the test samples sideways on.

Heinz Gotze concluded that the membranes had fulfilled all their requirements during the past 20 years and would almost certainly do so for at least another 20 years.

The team at AAC Waterproofing has been installing Prelasti for over 30 years. Our skills and experience ensures your flat roof is installed properly and lasts for decades.

Contact us today to begin the process of getting your new Prelasti EPDM flat roof.