Portslade, East Sussex
Kitchen-diner rear extension in Portslade
Kitchen-diner rear extension in Portslade: 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.
We cover Portslade (BN1, BN3 and BN41) as part of our East Sussex work. For Portslade 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 Portslade?
In Portslade, our guide for a kitchen-diner rear extension is £2,130–£3,470 per square metre including VAT for a standard specification. 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 |
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 Portslade?
Whether your kitchen-diner rear extension in Portslade 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 Portslade like to extend?
Commuter semis and detached houses make up much of Portslade, and longer gardens make England's prior approval route for deeper rear extensions worth considering.
How a kitchen-diner rear extension in Portslade 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.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Kitchen-diner rear extensions near Portslade
Neighbouring places we cover include Hove (2.3 miles) and Shoreham-by-Sea (2.6 miles).
- Kitchen-diner rear extension in Hove
- Kitchen-diner rear extension in Shoreham-by-Sea
- Kitchen-diner rear extension in Brighton
- Kitchen-diner rear extension in Lancing
- Kitchen-diner rear extension in Hurstpierpoint
Other work in Portslade:
FAQ
Kitchen-diner rear extension questions in Portslade
Can you match the brick or stone on my Portslade house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
Do you fit the kitchen?
Yes, whether you buy it yourself or we supply it. We take the measurements from the built shell, not the drawings.
What postcode areas do you cover around Portslade?
Including BN1, BN3 and BN41, and the surrounding East Sussex area.
Do I need planning permission for a rear extension in Portslade?
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.
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.