EPDM Rubber Roofing › Cardiff › Guide
Rear and side extensions are everywhere in Cardiff, and most are topped with a small flat roof. These roofs have awkward corners, a wall junction and a constant fight with rainwater. EPDM, a single-ply rubber membrane, has become a sensible choice for them because it can be laid with very few joints.
Fewer joints on a small roof
The membrane comes in large sheets, so a typical extension roof can often be covered in one piece. Every seam in a flat roof is a place where water can find a way in. On a small roof behind a Victorian terrace in Canton or Roath, covering the whole area in one sheet removes most of that risk.
Bonded to a sound deck
The sheet is stuck to the deck with adhesive, which holds it flat and stops wind getting under it. That only works if the deck is sound, dry and smooth. We check the boards, replace any that have rotted and make sure the surface is clean before the membrane goes down. A good sheet over a poor deck does not last.
- Boards must be sound, dry and firmly fixed.
- Rotten or sagging boards are replaced first.
- The surface is cleaned before bonding.
- Insulation is checked and kept in the right place.
Edges, upstands and corners
The detail matters more than the sheet. Where the extension meets the house wall, the membrane turns up as an upstand, and at the edges it finishes under trims. Corners are formed carefully rather than cut and patched. On Cardiff extensions that meet old brickwork we take particular care at the wall junction, which is where most flat roofs let go.
Falls and drainage
Water has to run to an outlet. If the falls are too flat or the gutter is blocked, water ponds and finds the weakest point. Where a roof ponds we look at fixing the falls as part of the work. EPDM does not fix a deck that holds water, so we deal with the cause before laying the membrane.
Suitable roofs and honest limits
EPDM suits garages, extensions, porches, dormer flats and small to medium flat roofs. Very large roofs may need joints, and a badly damaged deck needs more work. Where the membrane is sound, small repairs are possible without relaying everything. Our Flat Roofing South Wales section covers the wider range of flat roof options if you want to compare.
- Best on small and medium flat roofs.
- Large roofs may need seams, which we explain.
- Sound membranes can be patched or cured.
- A failed deck needs repair first.
Need epdm rubber roofing in Cardiff? See our epdm rubber roofing in Cardiff page, or call 07766 547309.
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Common Questions
Can EPDM be laid over the existing felt?
Sometimes, if the felt and deck are sound and dry. More often we strip back to the boards, repair them and start clean. We look at what is there and tell you which route makes sense for your roof.
Is EPDM good for a Cardiff extension that meets an old wall?
Yes, provided the wall junction is detailed carefully. The membrane turns up the wall as an upstand and is finished with a proper flashing or trim. We check the brickwork and the existing flashings before deciding on the details.
Do I need insulation under the membrane?
Often yes, particularly on a room that is lived in. Insulation affects how warm the room is and where condensation can form. We check what is there and what the extension needs, and advise before any work starts.
Get a Quote in Cardiff
Tell us what the roof is doing in Cardiff and we will look at it. Call 07766 547309, message us on WhatsApp or use the form below.