How to Prepare a Roof for EPDM Installation

October 8, 2018 | General
How to Prepare a Roof for EPDM Installation


EPDM roofing can have a lifespan of up to fifty years. The key to unlocking an EPDM roof’s full potential is to ensure it is installed to the highest standard. Rubber roofs that are fitted incorrectly or aren’t placed on top of suitable decking, aren’t going to last nearly as long as they should.

The reason for EPDM rubber’s popular and great reputation comes down to its ability to last for decades. So, to help you make sure that your EPDM rubber roof is installed correctly, here is a simple guide that tells you how to prepare a roof for EPDM installation.

What Can EPDM Be Installed On?

EPDM rubber roofing can be installed to a few different surfaces, but it works best when it adheres to timber deckings such as roofing grade plywood or OSB sterling board.

Sometimes EPDM can be bonded to lightweight concrete and other surfaces that are non-porous like fibreglass and tissue faced insulation. However, EPDM must not adhere to bitumen or asphalt because this will damage the material. Liquid mastics can also damage the EPDM.

If you are removing any of these materials or substances before installing EPDM, you must make sure that none is accidentally left behind. Some of these can leave a small residue which can affect how the EPDM performs once it is installed.

How to Prepare Roof Decking for EPDM

Once you have established your flat timber decking, there are some steps you must take to prepare for the EPDM. This will ensure a smooth and mistake-free installation, allowing your rubber roof to last as it should.

Step 1

Firstly, you must determine whether your timber decking is suitable or whether a new one needs to be installed. Look out for any rot because any rotting boards will need to be replaced before you install the EPDM roof.

Step 2

Then, you must ensure that the surface is clean. Sweep off any debris such as dust, dirt or loose material. It is also important to remove any oil, grease or rust, as these can prevent a smooth installation and can affect how the roof performs in the future.

Additionally, you should ensure there are no sharp objects on the decking or anything that may pierce or damage the EPDM when it is placed on top.

Step 3

Once the decking is clear of any debris, you must ensure the boards are properly fastened and are free of scuffs or holes. Any unsolid segments will either need to be refastened securely or replaced.

Step 4

The last thing you need to be sure of before installing your EPDM is that the timber decking is completely dry. The EPDM cannot be applied when the surface is wet, so you must start with dry boards or your installation will not work. This is also important because if you do manage to install an EPDM roof onto wet decking, it will not perform as well from that point forward.

Now your timber decking should be ready for installation. But, before you begin installing the EPDM rubber, you should also check that the adhesive you’re applying is suitable for the decking. Watch our handy youtube video to find out where to go from there. For more roofing guides about EPDM, see the rest of our blog or get in touch with today.

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