Double-storey extensions in Swansea
Thinking about a double-storey extension for your Swansea home? Start with a free site visit: we measure up, check what the council will allow and give you honest guide figures on the day.
- Guide price in SwanseaFrom £35,000 inc VAT
- PlanningUsually a planning application
- Build time16–24 weeks on site
- Postcode districtsSA1, SA2, SA3, SA5, SA6
Included in a typical project
- Insulation, plastering, electrics and plumbing to finish
- Ground and first floor structure, roof tied into the existing roof
- Building regulations drawings and structural design
- Foundations sized for two floors
- Breaking through at both levels, stairs and landing changes where needed
- Householder planning application where needed
Working in Swansea
Site visits are available across Swansea (SA1, SA2, SA3, SA5, SA6, SA7). The same team covers Clydach (5 miles), Briton Ferry (5 miles), Gorseinon (5 miles), Neath (7 miles), all within easy reach.
In Wales, terraced houses with rear offshoots are common in the towns, while detached houses and bungalows dominate in rural areas.
Guide prices for 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: £1,440 to £2,790 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m, two floors 24 m² | £35,000 – £42,500 | £40,000 – £52,500 | £51,000 – £67,000 |
| 4 m × 4 m, two floors 32 m² | £46,000 – £55,500 | £53,500 – £70,000 | £68,000 – £89,500 |
| 4 m × 6 m, two floors 48 m² | £69,000 – £83,000 | £80,000 – £105,000 | £102,500 – £134,000 |
Want a range for your exact size? The guide-price tool takes about a minute.
Planning rules that apply in Swansea
In Wales a rear extension of more than one storey can be permitted development only if the ground floor projects no more than 4 m, the upper floor no more than 3 m, it stays at least 10.5 m from the rear boundary and it is not in a conservation area, national park, National Landscape or World Heritage Site. Anything larger needs a planning application to the council.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
Building regulations approval is separate from planning. Wales has its own building regulations and approved documents; the council or a registered building control approver checks the plans, inspects the work and issues a completion certificate.
The Party Wall etc. Act 1996 applies in Wales as in England: notice must be served before work to a shared wall, building on the boundary, or excavating close to a neighbour's foundations.
Applications are decided by the local planning authority (your county or county borough council, or the national park authority).
From first visit to completion
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
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
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Your questions about a double-storey extension in Swansea
Do I need building regulations approval in Swansea?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Who do I contract with for a double-storey 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.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Swansea, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Is a two-storey extension cheaper per square metre?
Usually. Our guide range is about £1,440 to £2,790 per m² of new floor area including VAT, compared with £1,630 to £3,160 per m² for single-storey work, because the foundations and roof are shared across two floors.
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.