What is a kitchen extension?

A kitchen extension is an extension designed around a new kitchen, usually an open-plan kitchen, dining and family space at the back of the house. We build the extension and fit the kitchen as one project, so plumbing, electrics and lighting are planned around the layout from the start.
How much does a kitchen extension cost in Southsea?
In Southsea, a kitchen extension typically costs £2,500–£3,800 per m² including a mid-range kitchen, including VAT at 20% (standard rate). For a typical 22 m² project that is roughly £55,000–£83,500. That range is adjusted for the South East, where domestic building work typically costs around 12% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (15 m²) | £37,500–£57,000 |
| Typical project (22 m²) | £55,000–£83,500 |
| Larger project (31 m²) | £77,500–£118,000 |
| Rate per m² | £2,500–£3,800 |
The biggest cost drivers are:
- Glazing and roof lanterns
- Underfloor heating and flooring
- Kitchen units, worktops and appliances
- Who supplies the kitchen
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a kitchen extension in Southsea?
Here is how the rules work for a kitchen extension in England. In England a single-storey rear extension is often permitted development: broadly up to 3 metres deep on a semi-detached or terraced house and 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary, and covering no more than half the garden. The larger home extension scheme allows up to 6 or 8 metres if you notify the council first and neighbours have a chance to comment. In conservation areas, National Parks and National Landscapes the larger home extension route, side extensions and cladding are not permitted development. Flats and houses whose rights have been removed need a planning application, and listed buildings need listed building consent.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
From survey to sign-off, the job normally involves:
- Extension structure, roof and glazing
- Flooring and decoration
- Electrics, lighting plan and sockets
- Drainage and water supply positioned for the sink and appliances
- Kitchen layout planned alongside the extension design
- Extraction ducted to outside
How long does it take?
Allow 11 to 16 weeks on site, including kitchen fitting. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in Southsea
Commuter towns across the South East have many 1930s and post-war semis that suit rear extensions and hip-to-gable loft conversions.
Our Southsea coverage includes postcode districts PO4, and we also work in nearby places such as Portsmouth, Gosport and Ryde.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about kitchen extensions in Southsea
Is underfloor heating worth it?
In a large open-plan space it frees wall space for units and glazing and gives even heat. It is easiest to fit during the build.
Do you build kitchen extensions in Southsea?
Yes. We build kitchen extensions across Southsea, including postcodes PO4. Every project starts with a free home visit.
Will I need planning permission?
The same rules apply as for any extension. Many single-storey kitchen extensions are permitted development; larger or wraparound designs need an application.
How much does a kitchen extension cost in Southsea?
In Southsea, a kitchen extension typically costs £2,500–£3,800 per m² including a mid-range kitchen, including VAT at 20% (standard rate). A typical 22 m² project comes to roughly £55,000–£83,500. Your fixed price depends on the survey and drawings.
Can I buy my own kitchen?
Yes. You can supply it and we fit it, or we supply it as part of the price. Either way we coordinate deliveries with the build programme.
