Side extensions in Swansea: design, approvals and build
We design and build side extensions for houses in Swansea, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in SwanseaFrom £20,000 inc VAT
- PlanningSingle storey can be permitted development
- Build time10–18 weeks on site
- Postcode districtsSA1, SA2, SA3, SA5, SA6
What should I budget for a side extension in Swansea?
For Swansea we adjust our national guide rates by ×0.93, the factor we use for Wales. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Swansea: £1,630 to £3,160 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £20,000 – £25,000 | £22,500 – £30,000 | £29,000 – £38,000 |
| 3 m × 6 m 18 m² | £29,000 – £35,500 | £34,000 – £44,500 | £43,500 – £57,000 |
| 3 m × 8 m 24 m² | £39,000 – £47,000 | £45,500 – £59,500 | £58,000 – £76,000 |
Try the guide-price tool to see a range for your own size and finish.
Local to Swansea
Site visits are available across Swansea (SA1, SA2, SA3, SA5, SA6, SA7). Neighbouring towns we cover include Clydach (5 miles), Briton Ferry (5 miles), Gorseinon (5 miles), Neath (7 miles).
Llanelli, in Dyfed, is roughly 10 miles from Swansea and also on our list. In Wales, terraced houses with rear offshoots are common in the towns, while detached houses and bungalows dominate in rural areas.
Who a side extension suits
- Houses where the rear garden is small
- Detached and semi-detached houses with side land
- Homes needing a utility, study or ground-floor bedroom
Councils often prefer side extensions to sit slightly back from the front of the house with a lower roof, so the original building still reads clearly. We design to those principles from the start to avoid redesigns.
Planning rules that apply in Swansea
In Wales a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house, and it must not come closer to a highway than the existing side wall. Larger side extensions need planning permission.
The planning position for a specific Swansea address depends on its history and any designations, which is why we check it at the first visit.
Building over or within 3 m of a public sewer needs the water company's consent before the foundations go in.
Applications are decided by the local planning authority (your county or county borough council, or the national park authority).
What happens next
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Common questions in Swansea
Will my neighbours in Swansea be involved?
If a planning application is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
How long does a side extension take to build in Swansea?
On site, typically 10 to 18 weeks once approvals are in place. Before that, allow 6–14 weeks design and approvals.
Who do I contract with for a side extension in Swansea?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
How much does a side extension cost?
Our guide range is about £1,630 to £3,160 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £34,000 to £44,500 in Swansea.
Can I build over my driveway?
Yes, if the foundations work and you keep any parking the council requires. Drains and services under drives are common, so we check before design.
Book a free site visit in Swansea
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.