Handling Perimeter Walls and Internal Corners

In this guide, we will demonstrate how to tackle perimeter walls and internal corners on your EPDM flat roof installation. This ensures a watertight seal at traditionally vulnerable points on your flat roof and creates a neat finish for this high performance solution. Please download the full guide in PDF format with step-by-step instructions and colour images or read online using the 'Download Now' button.

Once the main field sheet is adhered the perimeter walls can be dealt with. With the membrane 150mm away from the perimeter wall, apply Bonding Adhesive to both the back of the membrane and also the area it is to be mated with.

When applying the bonding adhesive, all areas have to be cleaned and dry. The adhesive can be applied with either a small 4” roller or similar size paintbrush.

Care needs to be taken when using bonding adhesive. Spillages can swell the membrane, so it is worth keeping the adhesive and rollers away from the roof membrane. An offcut of EPDM is ideal as a base for the adhesive container.

Note: Bonding Adhesive is now dark green in colour.

Step 1.

Apply an even coat of adhesive to all surfaces to be mated.

Step 2.

Once the adhesive is tacky, offer up the membrane by rolling it into the angle change and then up the upstand wall. This method prevents any tenting of the membrane at the angle change.

Step 3.

When one wall is completed, repeat the procedure to the adjoining wall. An excess of material will collect in the corner, which needs to be tidied up and secured. This excess is commonly known as the “pig’s ear”.

Step 4.

The pig’s ear can be attached to either wall, whichever is convenient. It is necessary to fold the pig’s ear out of the way.

Step 5.

Apply contact adhesive inside the flap, wait until tacky, then mate it together.

Step 6.

Apply QuickPrime Plus primer on the back of the flap as shown. The flap will then adhere onto the upstand.

The following procedure will explain how the internal corner is formed on top of a parapet wall.

When one wall is successfully adhered, the adjoining wall can be dealt with. Mark a crayon line at the top of the wall and cut the membrane to the corner.

The pig’s ear can now be formed. All excess membrane is removed, and the membraned securely adhered.

A Quickseam Corner Flashing patch is the finishing detail for this corner, and this is applied with QuickPrime Plus. QuickPrime Plus and other Quickseam tapes are covered in more detail later in the manual.

When flashing up a wall, there are various options for termination. Lead flashing is a common finish as well as metal wall trim. If attaching metal wall trim into a wall chase, use Permaroof Bond and Seal to waterproof the top edge of this trim, and mechanically fix the trim to the perimeter wall with tech fixings.

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