What a rubber roof actually is
EPDM (ethylene propylene diene monomer) is a synthetic rubber membrane made for roofing. It arrives on site rolled up in large sheets, and on a typical garage or rear extension one sheet can cover the whole area. With no joins running across the middle, there are very few places for rain to get in.
The material stays supple in frost and heat, so it moves with the building rather than cracking. It has a matt black finish, which suits most extensions and outbuildings where the roof is out of sight.
How we install an EPDM roof
Installation begins by removing the old covering and looking hard at the deck. Rubber needs a smooth, dry, solid base, so any soft, rotten or uneven boards are replaced first. Edge trims and drip details are planned so water is led off the roof into the gutter.
The membrane is unrolled, allowed to relax and then bonded down with a water-based adhesive across the field of the roof, with a stronger contact adhesive at the perimeter and upstands. Corners, outlets and wall abutments are finished with purpose-made pieces, and the trims go on last to hold the edges tight.
If you are still deciding on a material, our GRP vs EPDM guide compares the two, and the GRP fibreglass roofing page covers the alternative in detail.
What affects rubber roof installation cost
We do not publish a price per square metre, because the membrane itself is only part of the bill. The things that move an EPDM roof installation cost up or down are:
- The size and shape of the roof, and how many corners, outlets and roof lights it has
- Whether the deck can stay or needs replacing, which is only known once the old felt is off
- Adding insulation to create a warm roof, which can raise the roof level and the trims
- Access, including whether scaffold or a tower is needed and how far materials have to be carried
- Removal and disposal of the old covering
EPDM roof replacement cost and when it makes sense
Replacing an old felt roof with rubber is one of the most common jobs we price. When you compare quotes, check whether each one includes new decking, trims and waste removal, because those items explain most of the gap between prices. Our flat roof replacement cost guide goes through the full list.
Lee gives you a fixed written figure after a free site visit, so you know the EPDM roof replacement cost before any work is booked.
Rubber roof repair and EPDM leak repair
A well-laid rubber roof rarely fails across its surface. When an EPDM roof leaks, the cause is usually at a detail: an edge trim that has lifted, an upstand that was never bonded properly, a puncture from a dropped tool or a branch, or a blocked outlet causing water to sit against a seam.
Most of these can be repaired with a patch of new membrane and the right primer and tape, without stripping the roof. If you are searching for rubber roof repair near you, call Lee and describe where the water is showing. Our flat roof repairs page explains how we assess any flat roof before deciding between a patch and a bigger job.
Where EPDM suits best
Rubber is a good fit for simple, regular roofs that see little foot traffic: garages, single-storey extensions, porches and dormer tops. Where a roof is walked on regularly or has lots of awkward detailing, GRP can be the better choice, and Lee will say so when he visits. You can read more about all our flat roof work on the main flat roofing page.