Rhiwbina, Cardiff and the Vale
Single-storey rear extension in Rhiwbina
Single-storey rear extension in Rhiwbina: ground-floor space across the back of the house, usually for a kitchen, dining or family room. We measure the house, show you what the rules allow, price it in writing and build it.
Rhiwbina is covered from our Cardiff and the Vale round, including CF14. A depth of 3 to 4 metres keeps many single-storey rear extensions in Rhiwbina within permitted development, subject to the house's planning history.
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 single-storey rear extension cost in Rhiwbina?
Guide prices for a single-storey rear extension in Rhiwbina start from our Wales rate of £1,770–£2,880 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 wide × 4 m deep (12 m²) | £21,000–£34,500 |
| 4 m wide × 5 m deep (20 m²) | £35,500–£57,500 |
| 4 m wide × 6 m deep (24 m²) | £42,500–£69,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a single-storey rear extension in Rhiwbina?
Here is how the rules in Wales apply to a single-storey rear extension in Rhiwbina.
In Wales a single-storey rear extension can often be permitted development if it projects no more than 4 metres beyond the rear wall and is no more than 4 metres high. Wales has no prior approval route for deeper extensions, so anything bigger needs a householder planning application.
Conservation areas, National Parks and National Landscapes restrict permitted development in Wales, and listed buildings need listed building consent. At the first visit we measure what is there now and tell you which route fits: permitted development or a householder planning application.
What are homes in Rhiwbina like to extend?
Older terraces near the centre and post-war semis further out are typical of Rhiwbina. Sloping sites are common in Wales, so floor levels and retaining walls are designed at the start.
How a single-storey rear extension in Rhiwbina comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
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.
Single-storey rear extensions near Rhiwbina
We also build single-storey rear extensions in nearby Whitchurch (1.2 miles) and Caerphilly (3.2 miles).
- Single-storey rear extension in Whitchurch
- Single-storey rear extension in Caerphilly
- Single-storey rear extension in Cardiff
- Single-storey rear extension in Penarth
- Single-storey rear extension in Llantrisant
Other work in Rhiwbina:
FAQ
Single-storey rear extension questions in Rhiwbina
How much does a single-storey rear extension cost in Rhiwbina?
As a guide, £1,770–£2,880 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £21,000–£34,500 at that rate. Your written price follows the survey.
Do I need planning permission for a rear extension in Rhiwbina?
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.
Does it add value to the house?
Nationwide's October 2025 house price research found that a 10% increase in floor area is linked to about 5% higher value on average. It is a guide, not a promise; local agents can tell you what extended homes on your street sell for.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
How long does a rear extension take to build in Rhiwbina?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Is the site visit in Rhiwbina free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.