Thornbury, Bristol and South Gloucestershire
Kitchen-diner rear extension in Thornbury
Kitchen-diner rear extension in Thornbury: an open-plan kitchen, dining and family room that opens straight onto the garden. We measure the house, show you what the rules allow, price it in writing and build it.
Thornbury sits in Bristol and South Gloucestershire, with postcode districts including BS35. For Thornbury kitchens we plan the extraction route and the island drainage before the slab is poured, so nothing has to be chased in later.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a kitchen-diner rear extension cost in Thornbury?
Guide prices for a kitchen-diner rear extension in Thornbury start from our South West England rate of £1,980–£3,220 per square metre, including VAT. South West prices run slightly above our West Midlands baseline; natural stone to match the house is the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £23,500–£38,500 |
| 4 m wide × 5 m deep (20 m²) | £39,500–£64,500 |
| 4 m wide × 6 m deep (24 m²) | £47,500–£77,500 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission for a kitchen-diner rear extension in Thornbury?
Planning for a kitchen-diner rear extension in Thornbury follows the English householder rules.
Under England's householder permitted development rules you can usually add 3 metres at the back of an attached house, or 4 metres on a detached house, without a planning application, as long as the extension stays under 4 metres high and its eaves stay under 3 metres where it is within 2 metres of a boundary.
England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Thornbury like to extend?
Stone-built and rendered houses are common around Thornbury, so matching the walling is a design decision in its own right: natural stone, reconstituted stone or a render finish across old and new.
How a kitchen-diner rear extension in Thornbury comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Kitchen-diner rear extensions near Thornbury
From Thornbury, the nearest places we also cover are Stoke Gifford (6.4 miles) and Yate (6.4 miles).
- Kitchen-diner rear extension in Stoke Gifford
- Kitchen-diner rear extension in Yate
- Kitchen-diner rear extension in Chepstow
- Kitchen-diner rear extension in Mangotsfield
- Kitchen-diner rear extension in Dursley
Other work in Thornbury:
FAQ
Kitchen-diner rear extension questions in Thornbury
Can you match the brick or stone on my Thornbury house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
What postcode areas do you cover around Thornbury?
Including BS35, and the surrounding Bristol and South Gloucestershire area.
How big should a kitchen-diner be?
Around 25 to 35 m² for the combined kitchen, dining and seating areas suits most family homes. Your survey shows what fits the house.
How much does a kitchen-diner rear extension cost in Thornbury?
As a guide, £1,980–£3,220 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £23,500–£38,500 at that rate. Your written price follows the survey.
How long does a rear extension take to build in Thornbury?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Do I need planning permission for a rear extension in Thornbury?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.