Cardiff, Cardiff and the Vale
Side return extension in Cardiff
Infilling the narrow passage beside a Victorian or Edwardian back addition. We design, get the approvals for and build side return 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 we check the boundary line and the neighbour's gutter before drawing a side return, because a few centimetres decide whether the wall goes on or beside the boundary.
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 side return extension cost in Cardiff?
Guide prices for a side return extension in Cardiff start from our Wales rate of £2,140–£3,530 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 |
|---|---|
| 2 m wide × 6 m deep (12 m²) | £25,500–£42,500 |
| 2.5 m wide × 7 m deep (17.5 m²) | £37,500–£62,000 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a side return extension in Cardiff?
Planning for a side return extension in Cardiff follows the Welsh householder rules.
In Wales a single-storey side extension can be permitted development if it is no more than 4 metres high and the house ends up no more than 50% wider than the original. Many side return infills on terraced streets, and most wraparounds, go through a householder application.
The Party Wall etc. Act 1996 also applies in Wales: two months' notice for work to a shared wall and one month for foundations dug close to a neighbour's building.
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 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 side return extension in Cardiff 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.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Side return extensions near Cardiff
We also build side return extensions in nearby Whitchurch (2.8 miles) and Penarth (2.9 miles).
- Side return extension in Whitchurch
- Side return extension in Penarth
- Side return extension in Rhiwbina
- Side return extension in Caerphilly
- Side return extension in Barry
Other work in Cardiff:
FAQ
Side return extension questions in Cardiff
How long does a rear extension take to build in Cardiff?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Can I combine a side return with a rear extension?
Yes; that is a wraparound extension, and it gives the biggest open-plan room a terrace can have.
How much does a side return extension cost in Cardiff?
As a guide, £2,140–£3,530 per square metre including VAT for a standard specification. For example, 2 m wide × 6 m deep (12 m²): about £25,500–£42,500 at that rate. Your written price follows the survey.
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 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.