St Austell, Cornwall
Kitchen-diner rear extension in St Austell
Thinking about a kitchen-diner rear extension in St Austell? An open-plan kitchen, dining and family room that opens straight onto the garden. Our team handles the drawings, the planning route and the build, and your contract is with one company throughout.
St Austell is covered from our Cornwall round, including PL25. For St Austell 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 St Austell?
In St Austell, our guide for a kitchen-diner rear extension is £1,980–£3,220 per square metre including VAT for a standard specification. 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 St Austell?
Here is how the rules in England apply to a kitchen-diner rear extension in St Austell.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres 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. Before any drawing we look up the property's history with the council, because earlier extensions and removed rights change the answer.
What are homes in St Austell like to extend?
Stone-built and rendered houses are common around St Austell, 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 St Austell 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.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Kitchen-diner rear extensions near St Austell
Close by, we work in Bodmin, about 9.2 miles away, and Truro, about 13.5 miles away.
- Kitchen-diner rear extension in Bodmin
- Kitchen-diner rear extension in Truro
- Kitchen-diner rear extension in Newquay
- Kitchen-diner rear extension in Falmouth
- Kitchen-diner rear extension in Redruth
Other work in St Austell:
FAQ
Kitchen-diner rear extension questions in St Austell
What postcode areas do you cover around St Austell?
Including PL25, and the surrounding Cornwall area.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
Can I add a utility room?
Often. A narrow utility or boot room along one side keeps the washing machine out of the open-plan space.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Can you match the brick or stone on my St Austell house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
How long does a rear extension take to build in St Austell?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.