Cardiff pitched roof extensions, designed and built
A pitched roof extension in Cardiff starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in CardiffFrom £20,500 inc VAT
- PlanningWelsh permitted development rules (rear up to 4 m)
- Build time10–16 weeks on site
- Postcode districtsCF5, CF10, CF11, CF14, CF23
Extensions in and around Cardiff
Our survey diary covers Cardiff, including CF5, CF10, CF11, CF14, CF23, CF24. We also work in nearby Penarth (3 miles), Barry (7 miles), Cowbridge (12 miles).
Welsh housing ranges from stone terraces in the valleys to render-and-slate houses and modern estates, and the Welsh planning rules differ from England's in several places.
What we take care of
- Insulation to current building regulations
- Lead or proprietary flashings to the main wall
- Roof windows positioned for light and ventilation
- Roof design matched to the existing pitch and tiles
Matching tiles is harder than it sounds. We source reclaimed or closest-match tiles where the originals are no longer made and agree samples with you before ordering.
Planning and approvals in Cardiff
In Wales a single-storey rear extension can usually project up to 4 m beyond the rear wall without a planning application, if it is no more than 4 m high, keeps eaves to 3 m and overall height to 4 m within 2 m of a boundary, and covers no more than half the land around the original house. Wales has no larger home extension prior approval scheme.
Homes in conservation areas, national parks, National Landscapes (AONBs) and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building regulations approval is separate from planning. Wales has its own building regulations and approved documents; the council or a registered building control approver checks the plans, inspects the work and issues a completion certificate.
Applications are decided by the local planning authority (your county or county borough council, or the national park authority).
Pitched roof extension prices in Cardiff
These guide figures apply our Wales adjustment (×0.93) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Cardiff: £1,720 to £3,260 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £20,500 – £24,000 | £23,500 – £31,000 | £30,500 – £39,500 |
| 4 m × 5 m 20 m² | £34,000 – £40,000 | £39,500 – £51,500 | £51,000 – £65,500 |
| 5 m × 6 m 30 m² | £51,500 – £60,000 | £59,500 – £77,000 | £76,500 – £98,000 |
For a figure based on your own dimensions, use our guide-price tool.
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Common questions in Cardiff
Who do I contract with for a pitched roof extension in Cardiff?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do I need building regulations approval in Cardiff?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How long does a pitched roof extension take to build in Cardiff?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 6–12 weeks design and approvals.
How much does a pitched roof extension cost?
Our guide range is about £1,720 to £3,260 per m² including VAT, a little more than a flat roof because of the roof structure and tiles.
Is a pitched roof better than a flat roof?
Neither is better in all cases. Pitched roofs blend with traditional houses and shed water quickly; flat roofs give more headroom and suit modern designs and lanterns.
Book a free site visit in Cardiff
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.