- 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
Cardiff at a glance
- Largest towns
- Cardiff, Whitchurch
- Postcode areas
- CF
- Building control
- Cardiff Council
- Neighbouring areas
- Vale of Glamorgan · Caerphilly · Newport · Rhondda Cynon Taf
- Guide price region
- Wales (−8% on West Midlands rates)
How much does an EPDM rubber roof cost in Cardiff?
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 Cardiff?
Flat roofs in Cardiff sit on 1960s and 1970s link-detached houses with flat-roofed garages and porches, newer estates where the first extension roofs are now being replaced and terraced streets with flat-roofed rear kitchens and bathrooms. 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 Cardiff the application goes to Cardiff Council. More on the rules.
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.
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.
Which towns in Cardiff do we cover?
EPDM rubber roofing in Cardiff: questions
Which towns in Cardiff do you cover?
All of Cardiff. 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 Cardiff?
£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 Cardiff?
It depends on where the roof is: in Cardiff that's Cardiff 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 a punctured EPDM roof be repaired?
Usually, yes. The area is cleaned and primed, then an EPDM patch or cover tape is bonded over the damage. If water has reached the deck, a survey first is sensible.
Can an EPDM roof be fitted in winter?
Yes, as long as the deck is dry. The adhesives are affected by cold and damp, so very cold or wet days can delay bonding, and the roof is kept temporarily weathertight between dry spells.
Can EPDM be laid over an old felt roof?
Sometimes, but we usually recommend stripping old felt first. Overlaying hides any rot or wet insulation underneath, and over a heated room a full replacement is often when insulation has to be added anyway.
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