How to install an EPDM rubber roof

This is a step by step tutorial in how to complete a one piece mebrane simple single garage roof, if you’re installing a roof adjoined to another building or a more complex roof in which you may need your roofing system to be moulded around a sky light you may need to seek out further information. Feel free to call us at 01484 794601 for any advice on installing your EPDM rubber roof.

What is EPDM rubber roofing?

EPDM is one of the most popular forms of modern flat roofing, having a proven track record for it’s durability and longevity, having a lifespan of up to 50 years with little maintenance if installed correctly. Praised for being DIY friendly EPDM rubber roofing is one of the simplest options to install even if you've never done it before. Often cut to the shape of your roof, leaving you with a singular piece of rubber membrane. It is much safer than traditional roofing systems, like felt requiring a naked flame during installation, rubber roofing opts to be cold fitted using water-based bonding adhesives. 

Tools/ Materials needed to install a EPDM rubber roof:

-            EPDM rubber Membrane

-            EPDM Water based adhesive

-            Contact Adhesive

-            Roller

-            Utility knife or scissors

-            Tape measure

-            Sweeping brush

-            Chalk

Step 1 – Preparing your roof deck.

Before you start to install you piece of EPDM rubber membrane, you want to ensure that you have a good foundation to start. You want the surface of your roof to be clean, free of dust and loose debris. You must ensure the surface of your roof is dry as it will not stick to wet surfaces, and you want to avoid trapping moisture under your membrane as it can cause later issues. The EPDM rubber roofing system is recommended to be installed onto on to fresh timber deck such as plywood or OSB Boards.

You should also check for any loose screws or anything creating an uneven surface this could lead to bubbles underneath your rubber or damage to the membrane.

Step 2 – Relaxing the membrane

When purchasing your EPDM rubber membrane, it will have been cut to the size of your roof, you should have requested enough overhang to cover the entirety of the roof whilst having at least 100mm of excess on each side of the roof. This allows for it to be tucked underneath any trims.

Unroll your membrane over the roof and let it relax for at least 30 minutes so that any folds, wrinkles or creases can flatten out, making the installation process easier.

Step 3 – Applying the adhesive to the deck

After letting your membrane rest, fold the rubber halfway, exposing the roof deck underneath. Afterwards, using a roller (preferably a 9” roller) apply the water based adhesive straight onto the deck, focusing on applying an even layer across the deck. Make sure to leave around 5 inches without adhesives around the perimeter of the deck. Roll the membrane back across the deck, whilst the adhesive is still wet, applying enough pressure to avoid leaving any air bubbles underneath your rubber.

If the adhesive begins to dry out you can apply a thin layer onto the back of the membrane. Be aware that the adhesive will dry quicker in hot weather conditions, so it is recommended to apply adhesive to a smaller area in hot weather.

Once completed, it is recommended to use a brush to sweep out any trapped air from underneath the rubber to ensure a longer lifespan and prevent later issues. Wait a few minutes and repeat this process on the other side of the deck.

Caution: Water based adhesives should only be applied in temperatures above 4 degrees, with no chance of reaching freezing conditions post 24-48 hours of installation.

Step 4 – Apply Contact Adhesive

After waiting 20 to 30 minutes, allowing for the membrane to bond to your roof deck, apply a thin layer of contact adhesive to the roof deck’s perimeter where you have left around 5 inches as well as the edges of the membrane. Ensure the contact adhesive is touch dry before rolling the rest of your membrane down.

Step 5 – Fitting your trims

Once your EPDM is fully stuck down, trim any excess. Once this is complete, it is recommended to install kerb trims and gutter edge trims where required in order to ensure your roofs longevity and maximize your investment. An EPDM roof, if correctly installed, with all trims can have an expected lifespan of up to 50 years.

Cut the trim to the required length if needed, all our kerb and gutter edge trims come with 6 pre-drilled holes to help secure your trim without cracking. Kerb trim is designed to direct the water to flow down into your gutter and the gutter edge trims allow the water to flow off the edge into the gutter. So, when measuring your roof for rubber ensure you measure with trims in mind, being aware if which side is your gutter. Flat roofs are not perfectly flat and should have a downfall, unless you have an outlet, this is the side you should be placing your gutter.