House extensions in South Glamorgan
Every type of house extension in South Glamorgan, from single-storey kitchen extensions to two-storey additions, side returns and orangeries. We design, handle the approvals and build.
- Towns listed4
- Price regionWales (×0.93)
- Planning rulesWales
- Postcode districts13
Towns we cover in South Glamorgan
Towns we cover here include Cardiff, Barry, Penarth, Cowbridge.
What extensions cost in South Glamorgan
We publish guide prices so you can budget before anyone visits. For South Glamorgan they are adjusted by ×0.93, the factor we use across Wales.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Wraparound extensions | 25 m² | £53,000 – £67,500 |
| Kitchen extensions | 20 m² | £39,000 – £49,500 |
| Conservatory replacement extensions | 14 m² | £27,500 – £36,000 |
| Side return extensions | 11 m² | £24,500 – £31,000 |
| Double-storey extensions | 32 m² | £53,500 – £70,000 |
| Orangery extensions | 16 m² | £41,500 – £52,500 |
| Extensions over a garage | 12 m² | £23,000 – £30,500 |
What works best for South Glamorgan houses?
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.
For many houses here, single-storey rear extensions, pitched roof extensions or side return extensions gives the most useful space for the budget.
Approvals for an extension in South Glamorgan
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.
In a conservation area, national park, National Landscape or World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
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.
Every extension type in South Glamorgan
- Flat roof extensions · from £19,500
- Orangery extensions · from £27,500
- Timber frame extensions · from £19,500
- Extensions over a garage · from £22,000
- Planning permission for extensions · from £300
- Porch extensions · from £3,700
- Extension plans and drawings · from £1,100
- Conservatory replacement extensions · from £18,500
- Pitched roof extensions · from £20,500
- Kitchen extensions · from £25,000
- Utility and boot room extensions · from £13,000
- Building regulations for extensions · from £800
- Glass box extensions · from £27,500
- Home office extensions · from £14,500
- Side return extensions · from £16,500
- Side extensions · from £20,000
- Bungalow extensions · from £24,000
- Wraparound extensions · from £33,000
- Double-storey extensions · from £35,000
- Single-storey rear extensions · from £19,500
- Bedroom extensions · from £24,000
- Annexe extensions · from £51,000
Neighbouring areas
Questions about extensions in South Glamorgan
How much does an extension cost in South Glamorgan?
With our Wales factor (×0.93), a standard-spec 20 m² single-storey extension is a guide £38,000 to £48,500 including VAT. Prices for every type are linked on this page.
Can I get a price before anyone visits?
Yes. This page shows guide prices adjusted for South Glamorgan, and the guide-price tool gives a range for your own size and finish in about a minute.
Will my neighbours need to be told?
If you apply for planning the council notifies them, and in Wales party wall notices may be needed for work near a shared boundary.
Who do I contract with?
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.
Book a free site visit in South Glamorgan
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.