Portland, Dorset
Kitchen-diner rear extension in Portland
We plan and build kitchen-diner rear extensions for homeowners in Portland. An open-plan kitchen, dining and family room that opens straight onto the garden. Start with a free site visit, then a written price once the design is agreed.
Portland sits in Dorset, with postcode districts including DT5. A kitchen-diner is often the reason people in Portland extend: the back kitchen in stone and rendered houses is rarely big enough for a table.
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 Portland?
A kitchen-diner rear extension in Portland is priced at £1,980–£3,220 per square metre including VAT as a guide, before kitchen fit-out and fees. 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 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a kitchen-diner rear extension in Portland?
The planning route for a kitchen-diner rear extension in Portland is set by England's householder rules and your council.
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 Portland like to extend?
Stone-built and rendered houses are common around Portland, 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 Portland comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
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 Portland
Close by, we work in Weymouth, about 3.3 miles away, and Dorchester, about 10.3 miles away.
- Kitchen-diner rear extension in Weymouth
- Kitchen-diner rear extension in Dorchester
- Kitchen-diner rear extension in Bridport
- Kitchen-diner rear extension in Swanage
- Kitchen-diner rear extension in Poole
Other work in Portland:
FAQ
Kitchen-diner rear extension questions in Portland
How long does a rear extension take to build in Portland?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
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.
Is the site visit in Portland free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
How much does a kitchen-diner rear extension cost in Portland?
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.
What postcode areas do you cover around Portland?
Including DT5, and the surrounding Dorset area.