How to Fit Metal Edge Trim Detail to EPDM Systems

In this guide, we will demonstrate how to fit metal edge trim to your EPDM flat roof installation. This method ensures a watertight and neat finish for this high performance solution. Please download the full, step-by-step guide with images in PDF format or read online using the 'Download Now' button.

Once the roof is watertight, the roof needs to be finished with metal edge trims. These are attached by mechanically fixing. The trims can be tailored with a sharp pair of tin snips. It is important that any cutting tools used are sharp, as blunt tools will damage the trims, and consequently, the cosmetic finish of the roof will appear unprofessional.

Care needs to be taken when handling the trims, as some cut edges are sharp and therefore a risk of damage to the membrane exists. It is good practice to radius the cut edges to take off the sharp point.

Before membrane installation, attach some 1” x 2” timber baton to create a water check kerb at all perimeter edges except for the gutter edge of the roof.

The membrane will be attached to the perimeter edges with Bonding Adhesive.

At the gutter edge, excess membrane needs to be trimmed off. Mark the membrane with the blunt edge of the scissors against the gutter (usually 100-150mm from the roof edge) and cut away the excess. The remaining membrane will fall naturally into the gutter at the correct length.

How to Fit Metal Edge Trim Detail | Permaroof Downloads

An excess of membrane at the gutter edge corners needs to be tidied up and secured. This excess can be folded around and glued or attached to the side of the roof edge with a hammer tacker.

Use the tin snips to cut the trims to size. For corner details, cut the top edge and also a V-shape in the trough at the bottom edge of the trim.

Bend the trims around the required angle.

Butyl sealing tape needs to be applied to the underside of the trims at the fixing points to waterproof the fixing penetration.

50mm x 25mm of tape is adequate for each fixing. The fixing points are evenly distributed and are generally 600mm apart. Apply the tape to the underside as shown, and peel off the backing paper.

Tech screws are used for attaching the trim. These screws cut through the trim, the butyl sealing tape and into the batten with no pilot holes required. Offer the trim to the desired position on the edge, and fix with a cordless screwdriver.



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Permaroof UK Ltd offers support for EPDM application, whether for trade roofers or for the DIY market. The resource library contains an extensive range of EPDM installation guides in downloadable PDF format and video tutorials with step-by-step instructions given by qualified and experienced EPDM specialists.



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