Bedroom extensions in Thame: design, approvals and build
Our design and build teams take on bedroom extensions in Thame, from the first measured survey through planning and building control to the finished room.
- Guide price in ThameFrom £29,000 inc VAT
- PlanningUsually a householder application
- Build time14–22 weeks on site
- Postcode districtsOX9
Extensions in and around Thame
We cover Thame and the postcode districts OX9. Nearby, we also take on projects in Oxford (12 miles), Bicester (13 miles), Henley-on-Thames (14 miles), Abingdon (14 miles).
Aylesbury, in Buckinghamshire, is roughly 9 miles from Thame and also on our list. The South East has a broad mix of 1930s semis, post-war estates, newer developments and period cottages, and many houses have enough garden for a generous rear extension.
Is a bedroom extension right for your house?
- Homeowners who want an en-suite master bedroom
- Multi-generational households
- Growing families
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.
Planning and approvals in Thame
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.
The planning position for a specific Thame 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, 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).
How much does a bedroom extension cost in Thame?
Prices below are for Thame, using the South East England factor of ×1.12. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Thame: £1,790 to £3,580 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| One bedroom 12 m² | £29,000 – £35,500 | £29,000 – £38,000 | £32,000 – £43,500 |
| Bedroom and en-suite 18 m² | £32,000 – £39,500 | £38,000 – £49,500 | £48,000 – £65,000 |
| Two rooms 30 m² | £53,500 – £66,000 | £63,500 – £82,500 | £80,500 – £108,000 |
Try the guide-price tool to see a range for your own size and finish.
How the project works
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
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
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.
Questions people ask about bedroom extensions
Who do I contract with for a bedroom extension in Thame?
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 Thame 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.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Thame, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Will a new bedroom need planning permission?
Upstairs additions usually do. Ground-floor rooms may fall within permitted development, depending on size and position.
How much does a bedroom extension cost?
Our guide range is about £1,790 to £3,580 per m² including VAT. A bedroom with an en-suite of about 18 m² is typically £38,000 to £49,500 at standard spec, depending on whether it is part of a larger two-storey build.
Book a free site visit in Thame
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.