Kitchen extensions with bedrooms above in Thornbury
Adding a kitchen extension with bedrooms above in Thornbury gives you two new rooms stacked on one footprint. Here's how we'd approach it, what it typically costs and the rules that apply in England.
Quick reference for homeowners in Thornbury.
- Postcode districts
- BS35
- County / area
- Gloucestershire, England
- Price region
- South West England
- Guide price
- £57,500–£78,000 (£2,060–£2,780 per m²), kitchen units and worktops priced separately
- Approval route
- It may be permitted development if it goes no more than 3 m beyond the original rear wall (counting any single-storey part) and stays 7 m from the rear boundary; otherwise it needs planning permission.
- Nearest towns
- Stoke Gifford (6.4 miles), Yate (6.4 miles), Severn Beach (7 miles)
- Distance to Gloucester
- about 21.3 miles
- First visit
- Free, no obligation
About a kitchen extension with bedrooms above
This service suits you if your kitchen is too small and you also need another bedroom. Building both floors at once costs less than a single-storey kitchen extension now and a first floor later. You get a layout that works for cooking, eating and the garden, a bedroom plan that works upstairs, the approvals your nation needs and the build, carried out by vetted teams working under S&K. Kitchen units are priced separately.
We cover postcode district BS35 in and around Thornbury, along with neighbouring Stoke Gifford, Yate and Severn Beach.
What it costs in Thornbury
Expect a kitchen extension with bedrooms above in Thornbury to land somewhere around £57,500–£78,000 (kitchen units and worktops priced separately) for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). Our South West England guide rate is £2,060–£2,780 per m², including VAT. Professional fees for drawings and the structural engineer are listed separately on our prices page.
| Spec | Per m² | A 4 m × 3.5 m footprint on two floors (28 m² of new floor space) |
|---|---|---|
| Essential | £1,900–£2,560 per m² | £53,000–£71,500 |
| Standard | £2,060–£2,780 per m² | £57,500–£78,000 |
| Premium | £2,470–£3,340 per m² | £69,000–£93,500 |
Planning and building regulations in Thornbury
In England, a two-storey rear kitchen extension can be permitted development if it goes no more than 3 m beyond the rear wall of the original house and stays at least 7 m from the rear boundary, with matching materials and roof pitch, outside protected areas. No balconies are allowed. Deeper designs need planning permission, costing £548 (or £575 for applications made from 8 December 2026).
Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.
Design points for Thornbury homes
Glazing and the Part L 25% rule
In England, new windows, roof lights and glazed doors in an extension are normally limited to 25% of the extension's floor area plus the area of any windows or doors removed. Larger glazing is possible, but needs SAP or compensating calculations, so we plan the rear doors around this from the start.
Bedrooms over a kitchen
Bedrooms above need an escape window or a protected route to the stairs, plus good sound insulation from the kitchen below. We position the stairs, landing and bedroom doors so the new rooms connect naturally to the existing first floor.
How we'd run your project
Understand the brief
At your home in Thornbury we agree what you need: bedroom count, bathroom, kitchen space, and how much garden you want to keep.
Plans, then approval
Measured survey, design, then the right approval route for your house. We explain each step before we take it.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.
Questions about kitchen extensions with bedrooms above in Thornbury
How long does a kitchen extension with bedrooms above take?
Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.
Which postcodes do you cover around Thornbury?
We cover Thornbury (BS35) and nearby places including Stoke Gifford, Yate and Severn Beach, plus the rest of Gloucestershire. The first site visit is free.
How much does a kitchen extension with bedrooms above cost in Thornbury?
Our guide for South West England, which covers Thornbury, is £2,060–£2,780 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 £57,500–£78,000 (kitchen units and worktops priced separately). Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
Is it cheaper to build a kitchen extension and bedrooms at the same time?
Yes, in most cases. Building both floors at once means one set of foundations, one roof, one scaffold and one set of approvals. Adding a first floor later means removing the original roof, possibly strengthening the foundations and disrupting the kitchen again. If you think you will need the bedroom, build it now.
Can I keep using my kitchen during the build?
For part of it. The new structure can be built while your existing kitchen stays in use, but when the rear wall is opened and the new kitchen is fitted there will be several weeks without one. We plan when this happens and help you set up a temporary kitchen elsewhere in the house.
Nearby
Close to Thornbury? We work across the area, including:
Other extensions in Thornbury
All two-storey extension services in Thornbury · Kitchen extensions with bedrooms above across Gloucestershire
Want a figure first? Try our guide price tool, then book a free visit to firm it up.