Covering Cowbridge
We work in Cowbridge (CF71) and the places around it, including Llantwit Major, Bridgend and Barry.
Homes in South Glamorgan
Housing in Wales ranges from terraced streets in the valleys and older industrial towns to stone-built homes in rural areas and modern estates around the cities.
What do you get with a double-storey extension?
Two-storey work has to sit comfortably with the house and the neighbours, so most of the design effort goes into the roofline, window positions and how the new first floor connects to the landing. We handle the planning application, the structural design and the building control process, then build, roof and finish both floors.
- Householder planning application
- Structural engineer’s design and calculations
- Foundations, steelwork, brick and block walls, roof
What will a double-storey extension cost?
What double-storey extensions typically cost. These are guide ranges; the written quote for your house replaces them.
| Double-storey extensions | Guide price incl. VAT |
|---|---|
| Standard specification | £2,400 to £2,900 per m² |
| Good specification | £2,900 to £3,400 per m² |
| High specification | £3,400 to £3,850 per m² |
What approvals does a double-storey extension need in Wales?
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.
Most two-storey extensions in Wales need householder planning permission from the council.
What can change the price or programme?
- Neighbours’ light is assessed using the 45-degree guide many councils use.
- The first-floor link can mean moving a bathroom or reshaping the landing.
What happens after I enquire?
- 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.
What people ask before starting
How much does a two-storey extension cost?
Typically about £2,400 to £3,850 per square metre of new floor area including VAT. A 40 m² extension across two floors is often around £100,000 to £150,000 depending on specification.
How long does a two-storey extension take?
Around 14 to 24 weeks on site, plus the planning period before that.
How do I get a price for double-storey extensions in Cowbridge?
Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.
Also covering
- Double-storey extensions in Llantwit Major
- Double-storey extensions in Bridgend
- Double-storey extensions in Barry
- Double-storey extensions in Whitchurch
Learn more about double-storey extensions, or see every project we cover in Cowbridge.

