Bedroom extensions in Bath: design, approvals and build
Bath homeowners can use us for the whole bedroom extension project: survey, design, planning or permitted development checks, building regulations and the build itself.
- Guide price in BathFrom £26,500 inc VAT
- PlanningUsually a householder application
- Build time14–22 weeks on site
- Postcode districtsBA1, BA2
Who a bedroom extension suits
- Growing families
- Homeowners who want an en-suite master bedroom
- Multi-generational households
New bedrooms on an upper floor need an escape window or a protected route to the outside under the building regulations. We design the window sizes and stair route to meet that from the outset.
Do I need planning permission in Bath?
In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
Covering Bath
We cover Bath and the postcode districts BA1, BA2. Neighbouring towns we cover include Keynsham (6 miles), Frome (10 miles), Nailsea (18 miles), Portishead (19 miles).
For homes towards Wiltshire, Trowbridge is around 8 miles away. South West homes range from terraced streets in the cities to stone cottages and bungalows in the countryside, and conservation areas are common in historic centres.
How much does a bedroom extension cost in Bath?
Prices below are for Bath, using the South West England factor of ×1.02. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Bath: £1,630 to £3,260 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| One bedroom 12 m² | £26,500 – £32,500 | £26,500 – £34,500 | £29,000 – £39,500 |
| Bedroom and en-suite 18 m² | £29,000 – £36,000 | £34,500 – £45,000 | £44,000 – £59,000 |
| Two rooms 30 m² | £48,500 – £60,000 | £58,000 – £75,000 | £73,000 – £98,000 |
For a figure based on your own dimensions, use our guide-price tool.
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions people ask about bedroom extensions
Who do I contract with for a bedroom extension in Bath?
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.
Will my neighbours in Bath be involved?
If a planning application or prior approval 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 bedroom extension take to build in Bath?
On site, typically 14 to 22 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.
Does an en-suite need a window?
No, but it needs mechanical extraction that meets the building regulations. We design the duct route at the drawing stage.
Will a new bedroom need planning permission?
Upstairs additions usually do. Ground-floor rooms may fall within permitted development, depending on size and position.
Book a free site visit in Bath
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.