Cardiff, Cardiff and the Vale
Two-storey rear extension in Cardiff
A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. We design, get the approvals for and build two-storey rear extensions in Cardiff and the surrounding area, with one contract from the first survey to building control sign-off.
We cover Cardiff (CF3, CF5, CF11 and CF14) as part of our Cardiff and the Vale work. In Cardiff, a two-storey rear extension is worth comparing with the cost of moving once stamp duty, agents' and legal fees are counted.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a two-storey rear extension cost in Cardiff?
Guide prices for a two-storey rear extension in Cardiff start from our Wales rate of £1,670–£2,510 per square metre, including VAT. Prices in Wales sit below our West Midlands baseline; sloping sites are the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m × 5 m footprint, two floors (30 m²) | £50,000–£75,500 |
| 4 m × 6 m footprint, two floors (48 m²) | £80,500–£120,500 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a two-storey rear extension in Cardiff?
Whether your two-storey rear extension in Cardiff needs a planning application depends on its size, your house and any local restrictions.
In Wales a rear extension of more than one storey can be permitted development if the ground floor projects no more than 4 metres and the upper floor no more than 3 metres, with at least 10.5 metres to the rear boundary. It is not permitted development in conservation areas, National Parks or National Landscapes, so many double-storey schemes need a householder application.
Conservation areas, National Parks and National Landscapes restrict permitted development in Wales, and listed buildings need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Cardiff like to extend?
Cardiff has Victorian terraces near the centre and semis further out. Welsh permitted development allows up to 4 metres at the rear for many houses.
How a two-storey rear extension in Cardiff comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Paperwork handled
Planning or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Two-storey rear extensions near Cardiff
From Cardiff, the nearest places we also cover are Whitchurch (2.8 miles) and Penarth (2.9 miles).
- Two-storey rear extension in Whitchurch
- Two-storey rear extension in Penarth
- Two-storey rear extension in Rhiwbina
- Two-storey rear extension in Caerphilly
- Two-storey rear extension in Barry
Other work in Cardiff:
FAQ
Two-storey rear extension questions in Cardiff
What postcode areas do you cover around Cardiff?
Including CF3, CF5, CF11, CF14, CF23 and CF24, and the surrounding Cardiff and the Vale area.
Can you match the brick or stone on my Cardiff house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
Is two-storey cheaper per square metre than single-storey?
Usually yes, because the foundations and roof are shared across twice the floor area. The total cost is higher.
Do I need planning permission for a rear extension in Cardiff?
Often not for a single-storey rear extension of up to 4 metres under Welsh permitted development. Wales has no prior approval route for deeper extensions.
Is the site visit in Cardiff free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
Do you handle building control in Cardiff?
Yes. We apply to the council or a registered approver under the Welsh regulations and hand over the completion certificate.