Portsmouth, Hampshire
Kitchen-diner rear extension in Portsmouth
Kitchen-diner rear extension in Portsmouth: 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.
Portsmouth and its postcode districts PO1, PO2, PO3 and PO4 are part of our Hampshire coverage. A kitchen-diner is often the reason people in Portsmouth extend: the back kitchen in inter-war semis and 1960s estates 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 Portsmouth?
A kitchen-diner rear extension in Portsmouth is priced at £2,130–£3,470 per square metre including VAT as a guide, before kitchen fit-out and fees. South East prices run above our West Midlands baseline, mainly on labour rates and clay-soil foundations.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £25,500–£41,500 |
| 4 m wide × 5 m deep (20 m²) | £42,500–£69,500 |
| 4 m wide × 6 m deep (24 m²) | £51,000–£83,500 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a kitchen-diner rear extension in Portsmouth?
Whether your kitchen-diner rear extension in Portsmouth needs a planning application depends on its size, your house and any local restrictions.
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. 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 Portsmouth like to extend?
Around Portsmouth the housing ranges from inter-war semis to 1960s and 1970s estates with good-sized gardens. Many of the newer estates had permitted development rights removed by condition, so we check the planning history before anything is drawn.
How a kitchen-diner rear extension in Portsmouth 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.
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 Portsmouth
Close by, we work in Southsea, about 1.1 miles away, and Gosport, about 1.7 miles away.
- Kitchen-diner rear extension in Southsea
- Kitchen-diner rear extension in Gosport
- Kitchen-diner rear extension in Cosham
- Kitchen-diner rear extension in South Hayling
- Kitchen-diner rear extension in Fareham
Other work in Portsmouth:
FAQ
Kitchen-diner rear extension questions in Portsmouth
How long does a rear extension take to build in Portsmouth?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
What postcode areas do you cover around Portsmouth?
Including PO1, PO2, PO3, PO4, PO5 and PO6, and the surrounding Hampshire area.
Should the sink face the garden?
If the plan allows, an island sink or hob facing the glass is a common choice. It needs a floor-level drain run, which is easy to lay in a new slab.
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.
Is the site visit in Portsmouth free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.