- Price per m²
- £60–£106
- Typical life
- 25–50 years
- Manufacturer guarantees
- 20-year material warranties are common
- Typical garage roof
- £1,450–£2,600
Gwynedd at a glance
- Largest towns
- Bangor, Gwynedd, Caernarfon
- Postcode areas
- LL
- Building control
- Gwynedd Council
- Neighbouring areas
- Isle of Anglesey · Conwy · Denbighshire · Flintshire
- Guide price region
- Wales (−8% on West Midlands rates)
How much does an EPDM rubber roof cost in Gwynedd?
Guide prices including VAT at Wales rates. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Single garage (18 m²), EPDM rubber | £1,450–£2,600 |
| Extension (20 m²), EPDM, new deck + insulation | £2,600–£4,500 |
| Porch or bay (4 m²), EPDM | £700–£1,150 |
Which flat roofs are common in Gwynedd?
Flat roofs in Gwynedd sit on 1930s semis with flat-roofed garages and kitchen extensions, terraced streets with flat-roofed rear kitchens and bathrooms and low-rise post-war blocks of flats. Wales averages roughly 1,460 mm of rain a year, among the wettest in Britain, so we design for steady run-off: proper falls, clear outlets and upstands well above the finished roof. Approximate 1991–2020 regional averages based on Met Office data.
Building regulations in Wales
Welsh guidance is that most re-roofing needs building control approval, so it's worth checking whenever more than a quarter of a roof is replaced or repaired. Renovated roofs are upgraded to around 0.16 W/m²K where feasible, and new extension roofs are built to 0.13 W/m²K under the Welsh Approved Document L. In Gwynedd the application goes to Gwynedd Council. More on the rules.
Do I need building regulations approval to replace a roof with EPDM?
Often, yes. In England, Wales and Northern Ireland, re-covering more than half of a flat roof over a heated room usually counts as renovating a thermal element, so the roof should be insulated towards the renovation standard where that is feasible; in Scotland, the council's building standards service decides whether a building warrant is needed.
An unheated detached garage normally falls outside these rules, and a patch repair is treated differently from a full re-cover.
In practice that means a warm roof: insulation above the deck, a vapour control layer beneath it and the EPDM on top. The extra thickness lifts the finished roof, so at survey we check door thresholds, window cills, wall flashings and upstand heights, aiming for an upstand of about 150 mm above the finished surface. Where approval is needed, we deal with building control or building standards for you. The building regulations page and our warm vs cold roof guide go into more detail.
How are the joins, edges and upstands made watertight on an EPDM roof?
They are bonded with contact adhesive and sealed with purpose-made EPDM tapes and pre-formed pieces, because the edges and details are where most rubber roof leaks start.
- Wall upstands: the rubber is turned up the wall, usually to about 150 mm above the finished roof, fully bonded, then finished with a termination bar or a cover flashing chased into the masonry.
- Corners: folded rather than cut where possible, or finished with pre-formed pieces.
- Joins: on roofs wider than one sheet, the laps are cleaned, primed and joined with splice tape, then rolled firmly.
- Pipes and vents: sealed with pre-formed pipe boots rather than relying on mastic.
- Edges and outlets: drip and kerb trims are fixed and the junction with the membrane is sealed with cover tape; outlets are bonded into the membrane at the lowest point.
We also check the falls before laying, because standing water around an outlet shortens the life of any detail. There is more on this in our pages on edges and drainage and rooflight upstands.
Which towns in Gwynedd do we cover?
EPDM rubber roofing in Gwynedd: questions
Which towns in Gwynedd do you cover?
All of Gwynedd. The main towns have their own pages below, and if yours isn't listed we still cover it: send your postcode and we'll confirm.
How much does an EPDM rubber roof cost in Gwynedd?
£1,450–£2,600 for a typical 18 m² garage roof in EPDM, at Wales guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which council handles building control for a flat roof in Gwynedd?
It depends on where the roof is: in Gwynedd that's Gwynedd Council. Welsh guidance is that most re-roofing needs building control approval, so it's worth checking whenever more than a quarter of a roof is replaced or repaired. We confirm which applies at the survey.
Can you put a green roof on top of EPDM?
Yes. EPDM is often used under sedum, with a protection layer, drainage and growing medium laid on top. The structure must be able to carry the extra weight, which we check before quoting.
Does an EPDM roof need maintenance?
Very little. Clear leaves from outlets and gutters, look over trims and upstands once or twice a year and after storms, and keep foot traffic to a minimum.
Can you walk on an EPDM roof?
Occasionally, for maintenance, yes, but EPDM is not designed as a regular walking surface. Where you need a route to plant or windows, walkway pads can be bonded on, or GRP may be a better fit.
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