- Guide price
- £700–£1,150
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
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 a porch or bay 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 |
|---|---|
| Porch or bay (4 m²), EPDM | £700–£1,150 |
| Single garage (18 m²), EPDM rubber | £1,450–£2,600 |
| Extension (20 m²), GRP, new deck + insulation | £2,750–£4,950 |
Which flat roofs are common in Cardiff?
Flat roofs in Cardiff sit on lock-up garage blocks on estates, 1930s semis with flat-roofed garages and kitchen extensions and bungalows with flat-roofed side extensions and dormers. 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 long does a porch roof replacement take?
Most porch and bay roofs are replaced in a single day, weather permitting. GRP or liquid systems may need a return visit for a topcoat once the first coat has cured.
Disruption is minimal. You may need to use another door while a front porch is being re-roofed, and the area below should be kept clear for safety. A ground-floor bay can usually be reached from a tower or platform steps, while a first-floor bay may need a small scaffold. The window below stays usable, though it is best kept closed while resin is curing.
Why do small porch and bay roofs carry a minimum charge?
Because a small roof needs nearly the same set-up as a larger one: a team, safe access, materials, trims, waste removal and travel. The roof area is only part of the cost.
A 2 m² canopy and a 6 m² bay still both need a full strip, a deck check, edge trims, a wall flashing and the same care at the drip edge. That is why our full re-roofs carry a minimum charge rather than being priced purely per square metre. It is also why bundling makes sense: if you have a porch, a bay and a garage, pricing them together usually works out better than three separate visits.
The junction with the house wall deserves the most attention on a porch. Many leaks blamed on a porch roof are actually water tracking behind a failed flashing or through porous brickwork above. We check the wall, the flashing and the frame head before recommending a new roof. If the problem is only the flashing, a targeted repair may be enough. Our flat roof leaks guide explains how leaks are traced.
Which towns in Cardiff do we cover?
Porch, bay and canopy roofs 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 a porch or bay roof cost in Cardiff?
£700–£1,150 for a small 4 m² porch or bay 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 you re-roof a porch and a garage on the same visit?
Yes, and it is often better value. Combining small roofs spreads the set-up and travel costs.
Should I replace lead on my bay roof with EPDM or GRP?
It depends on the house and your priorities. Membranes usually cost less and have no scrap value to thieves, but on a period or listed property keeping a lead appearance may matter or be required.
Can a canopy over a front door be re-covered?
Yes. Small canopies are re-covered in the same way as porches, usually in EPDM or GRP, subject to the minimum charge.
Everything about porch, bay and canopy roofs → · All flat roofing in Cardiff →