Extra bedroom and en-suite extensions in Swansea
For an extra bedroom and en-suite extension in Swansea, the first questions are always the same: how big, which approvals, and what it will cost. This page answers all three for Swansea and Neath Port Talbot.
Useful details for planning an extra bedroom and en-suite extension in Swansea.
- Postcode districts
- SA1, SA2, SA3 and SA5
- County / area
- Swansea and Neath Port Talbot, Wales
- Price region
- Wales
- Guide price
- £51,500–£69,500 (£1,840–£2,480 per m²), plus £5,500–£11,000 for the en-suite
- Approval route
- It may be permitted development if the ground floor goes no more than 4 m and the first floor no more than 3 m beyond the original rear wall, with the first floor 10.5 m from the rear boundary.
- Nearest towns
- Clydach (4.7 miles), Briton Ferry (5.4 miles), Gorseinon (5.4 miles)
- First visit
- Free, no obligation
About an extra bedroom and en-suite extension
An extra bedroom and en-suite extension is a two-storey extension planned around a new double bedroom with its own shower room on the first floor, with a ground-floor room below. It is one of the most effective ways to add space for a growing family. Nationwide's 2025 research linked adding a double bedroom and bathroom to a three-bed, one-bathroom house with value gains of up to 24%.
Around Swansea we also work in Clydach, Briton Ferry and Gorseinon, and across the rest of Swansea and Neath Port Talbot. Postcode districts in and near Swansea: SA1, SA2, SA3 and SA5.
What it costs in Swansea
Guide prices for extra bedroom and en-suite extensions in Wales are around £1,840–£2,480 per m² of new floor space, including VAT. For a typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space), that's roughly £51,500–£69,500 (plus £5,500–£11,000 for the en-suite). We'll give you a written design-stage price first, then a fixed build price once the drawings are agreed.
| Spec | Per m² | A 4 m × 3.5 m footprint on two floors (28 m² of new floor space) |
|---|---|---|
| Essential | £1,690–£2,290 per m² | £47,500–£64,000 |
| Standard | £1,840–£2,480 per m² | £51,500–£69,500 |
| Premium | £2,210–£2,980 per m² | £62,000–£83,500 |
Planning and building regulations in Swansea
In Wales, an extra bedroom at the rear can be permitted development if the first floor goes no more than 3 m beyond the original rear wall and stays 10.5 m from the rear boundary. A two-storey side extension can also qualify if it is 10.5 m from the side boundary, set back 1 m and adds no more than 50% width. Otherwise the fee is £585.
Approval in Wales: Householder planning application: £585. Councils normally decide householder applications within 8 weeks.
Building regulations: Building regulations approval under the Welsh Approved Documents, which differ from England's in places (notably energy efficiency).
Design points for Swansea homes
Planning the en-suite
An en-suite needs a route for the soil pipe to the drains, enough fall for waste water and an extract fan to the outside under Part F. Placing it over the ground-floor utility or near an existing drain keeps pipework short and hidden.
Escape window and fire safety
A new first-floor bedroom needs an escape window with a clear opening of at least 0.33 m², at least 450 mm wide and high, and the bottom no more than 1,100 mm above the floor, unless there is a protected route to the stairs. We design the windows to meet this.
How we'd run your project
Free site visit
We visit your home in Swansea, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Design and approvals
We draw the extension and check it against the rules for Wales, then apply for planning permission or a certificate of lawfulness, whichever fits.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.
Questions about extra bedroom and en-suite extensions in Swansea
Who handles building regulations for a project in Swansea?
We handle it as part of the project. What's needed in Wales: building regulations approval under the Welsh Approved Documents, which differ from England's in places (notably energy efficiency). We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
Which postcodes do you cover around Swansea?
We cover Swansea (SA1, SA2, SA3 and SA5) and nearby places including Clydach, Briton Ferry and Gorseinon, plus the rest of Swansea and Neath Port Talbot. The first site visit is free.
How much does an extra bedroom and en-suite extension cost in Swansea?
Our guide for Wales, which covers Swansea, is £1,840–£2,480 per m² including VAT. A typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) comes to about £51,500–£69,500 (plus £5,500–£11,000 for the en-suite). Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
How big should a new double bedroom be?
There is no legal minimum size for a bedroom in a house you own, so the test is whether it works. A comfortable double needs room for the bed with space to walk round it, wardrobes and a door that opens freely. We draw furniture on the plans so you can judge the space before anything is built.
What goes on the ground floor below a new bedroom?
Whatever suits you: a bigger kitchen, a family room, a study, a utility or a downstairs shower room. The ground floor usually costs about the same whatever it is used for, apart from kitchen units and bathroom fittings, which are priced separately.
Nearby
Other towns near Swansea:
Other extensions in Swansea
All two-storey extension services in Swansea · Extra bedroom and en-suite extensions across Swansea and Neath Port Talbot
Want a figure first? Try our guide price tool, then book a free visit to firm it up.