Flat roofing has come a long way from the leaky felt garages of the past. This 2026 guide compares the main flat-roofing systems for Dublin homes, EPDM rubber against GRP fibreglass and the older felt and single-ply options, so you can pick the right roof for Irish weather and know what a job costs before you commit.
Four systems cover almost every flat roof we install or repair in Dublin. Each behaves differently under Irish rain and freeze-thaw, and each has a different working life.
EPDM rubber is a single sheet of synthetic rubber, cold-applied with no seams on most domestic roofs. It flexes with temperature, shrugs off UV and standing water, and lasts 30 to 50 years. It is our default recommendation for Dublin homes.
GRP fibreglass is a glass-reinforced resin laid wet and cured into one solid, seamless skin. It gives a hard, walk-on finish that suits balconies and dormers, but it is more brittle in freeze-thaw and typically lasts 20 to 30 years.
Felt, whether torch-on or built-up, is the traditional option. Modern torch-on felt is far better than the old three-layer stuff, but it still has the shortest life at 10 to 20 years and needs a naked flame to install. Single-ply membranes such as PVC and TPO are mostly a commercial choice, heat-welded at the seams for large flat areas.
For a typical Dublin extension, garage or dormer, the real choice comes down to EPDM against GRP. Felt still earns its place on tight budgets and small outbuildings, but on anything you want to forget about for a few decades, rubber or fibreglass is money better spent.
Dublin flat roofs take constant rain, wind-driven wet and a run of frosts every winter. That combination is hard on any material that cannot move. EPDM stays flexible in the cold and handles the standing water a flat roof inevitably holds, which is why it outlasts the alternatives here. GRP performs well too, but its rigid surface is more prone to hairline cracking where a building shifts or the deck flexes.
We are Firestone-approved EPDM installers and we work cold-applied, with no naked flame, so there is no torch risk to your home or extension. On coastal Dublin, from Clontarf out to the bay, salt air also degrades old felt and metal trims faster, which pushes even more jobs towards rubber.
Drainage matters as much as the material. A flat roof is never truly flat, and the ones that fail early are usually the ones laid dead level with nowhere for water to go. When we install, we build in firrings to create a slight fall and set the outlets so rain clears quickly, which is often the difference between a roof that lasts its full life and one that ponds and splits after a few winters.
Every roof is different, but these are honest Dublin ranges for 2026. We give you a written, fixed-price quote after a free survey, so nothing changes on completion.
What moves the price is the size and shape of the roof, the state of the timber deck underneath, access, and how many upstands, outlets and trims are involved. A quick survey usually tells us which side of the range you are on. As a guide, a small garage or porch roof sits at the lower end, while a wraparound kitchen extension with rooflights and multiple upstands sits nearer the top.
If the deck below is sound and the leak is localised, a targeted repair is the right and cheaper call, usually €350 to €900. Once you see bubbling, splits across the surface, ponding that never drains, or damp spreading on the ceiling below, the covering has reached the end of its life and a full re-cover is the better spend.
A replacement is a tidy job. We strip the old covering, check and repair the timber deck, add insulation and firrings to create a slight fall so water runs off, then lay the new membrane with fresh trims and outlets. Most domestic flat roofs, an extension, garage or dormer, are finished in one to three days.
It is worth catching a failing flat roof early. Water that gets past the covering soaks into the timber deck and insulation, and once that is wet the repair grows from a covering job into a structural one. If you can see ponding, blistering or a stain forming on the ceiling below, a free survey now usually saves money later.
Flat roofs are the workhorse of extensions, garages, dormers and small commercial units, so getting the covering right matters. As a CIRI-registered contractor with €6.5M insurance and a 10-year written guarantee on our work, we install to last rather than to the lowest price. You can read more about our full flat roofing service, or call our Dublin team for straight advice.
Learn more about our flat roofingWe cover flat roofing across all of Dublin from our head office, including suburbs such as Rathfarnham, Dundrum and Clontarf. Pick your area for local detail, or call us and we will tell you straight away whether your flat roof needs a repair or a re-cover.
For most Dublin homes, EPDM rubber is the best choice. It stays flexible through frost and freeze-thaw, copes with the standing water a flat roof always holds, and resists UV and salt air, giving it a 30 to 50 year life. GRP fibreglass is a strong second where a hard walk-on surface is needed.
Both are seamless and durable, but they suit different jobs. EPDM rubber is more flexible, handles freeze-thaw and movement better, and lasts longer at 30 to 50 years, which makes it our default for Dublin roofs. GRP fibreglass gives a harder, walk-on finish ideal for balconies and dormers, but it is more brittle in frost and typically lasts 20 to 30 years.
It depends on the material. EPDM rubber lasts 30 to 50 years, GRP fibreglass 20 to 30 years, and felt or torch-on the least at 10 to 20 years. A well-installed roof with a proper fall for drainage always outlasts a cheap covering laid flat, so installation quality matters as much as the material.
In 2026, EPDM and GRP both run about €80 to €120 per square metre supplied and fitted. A typical domestic extension flat roof costs €2,500 to €6,000, while a localised flat-roof repair is €350 to €900. You get a written, fixed price after a free survey, so the figure never changes on completion.
Yes, a flat roof can be converted to a low pitch, and it can improve drainage and appearance on an extension or garage. It is a bigger job than a re-cover, as it adds new timber structure and tiles or slates, and it may need planning permission if it changes the roofline. In many cases a quality EPDM roof laid with a proper fall solves the drainage problem for far less, and we will advise you honestly on the survey.
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