Covering South Glamorgan
Our coverage across South Glamorgan includes Cardiff, Barry, Penarth and Llantwit Major.
Homes in South Glamorgan
Welsh homes include long terraces built into hillsides, stone cottages and modern estates, and sloping sites often shape how and where an extension can go.
What is a side return extension?
Side returns are small in area but heavy in detail: party walls, a glazed roof, and steelwork to take out the original back wall. We design the roof for light and drainage, agree the party wall process early, and keep the work tidy because access is often through the house.
- Planning and building regulations checks under Welsh rules
- Party wall notices and surveyor liaison
- Underfloor heating ready screed if wanted
What will a side return extension cost?
Typical ranges for side return extensions. Ground conditions, access and specification move the final figure, which we fix in writing before work starts.
| Side return extensions | Guide price incl. VAT |
|---|---|
| Standard specification | £3,350 to £3,700 per m² |
| Good specification | £3,700 to £4,150 per m² |
| High specification | £4,150 to £4,550 per m² |
Do you need permission for a side return extension in South Glamorgan?
In Wales the planning rules, including what counts as permitted development, are set by the Welsh Government, and Welsh building regulations differ in places from England’s. We check both against your house before drawings are finalised, and handle party wall notices where needed.
Wales has its own permitted development rules, set by the Welsh Government. Small single-storey rear extensions can often go ahead without an application, but the limits differ from England's and there is no larger-extension prior approval route, so we check the current Welsh rules for your house before drawings are finalised.
What can affect a side return extension?
- Access is often through the house, so we plan deliveries and protect floors.
- Many terraces sit in conservation areas, where side extensions need planning permission.
From first call to completion
- Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
- Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
- Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
- Construction and completion. One site lead co-ordinates every trade through to the building control certificate.
Your questions answered
How much does a side return extension cost?
Usually about £3,350 to £4,550 per square metre including VAT, which works out at around £35,000 to £55,000 for a typical side return before the kitchen.
How long does a side return take?
About 10 to 14 weeks on site.
Do you work in South Glamorgan?
Yes. South Glamorgan is within our coverage for side return extensions, along with nearby Cardiff and Barry.
Side return extensions near South Glamorgan
- Side return extensions in Cardiff
- Side return extensions in Barry
- Side return extensions in Penarth
- Side return extensions in Llantwit Major
- Side return extensions in Whitchurch
- Side return extensions in Cowbridge
Learn more about side return extensions, or see every project we cover in South Glamorgan.

