House extensions in West Sussex
From a small utility to a two-storey addition, we take on house extensions throughout West Sussex, starting with a free visit and a planning check.
- Towns listed12
- Price regionSouth East England (×1.12)
- Planning rulesEngland
- Postcode districts32
Towns we cover in West Sussex
Towns we cover here include Crawley, Worthing, Bognor Regis, Littlehampton.
What extensions cost in West Sussex
Use these West Sussex guide prices to sense-check a budget; the guide-price tool narrows them to your own size, and the site visit turns them into a written figure.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Wraparound extensions | 25 m² | £64,000 – £81,500 |
| Single-storey rear extensions | 20 m² | £45,500 – £58,500 |
| Double-storey extensions | 32 m² | £64,500 – £84,500 |
| Orangery extensions | 16 m² | £50,000 – £63,000 |
| Conservatory replacement extensions | 14 m² | £33,500 – £43,500 |
| Extensions over a garage | 12 m² | £28,000 – £36,500 |
| Side return extensions | 11 m² | £29,500 – £37,000 |
Approvals for an extension in West Sussex
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
What works best for West Sussex houses?
In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
Depending on the plot, double-storey extensions and single-storey rear extensions are often the strongest options, with wraparound extensions worth considering where there is room.
Choose an extension type
- Flat roof extensions · from £23,500
- Bedroom extensions · from £29,000
- Bungalow extensions · from £29,000
- Glass box extensions · from £33,500
- Orangery extensions · from £33,500
- Planning permission for extensions · from £350
- Side extensions · from £24,500
- Utility and boot room extensions · from £15,500
- Wraparound extensions · from £40,000
- Porch extensions · from £4,450
- Pitched roof extensions · from £24,500
- Building regulations for extensions · from £1,000
- Single-storey rear extensions · from £23,500
- Kitchen extensions · from £30,000
- Side return extensions · from £20,000
- Double-storey extensions · from £42,500
- Extension plans and drawings · from £1,300
- Extensions over a garage · from £26,500
- Annexe extensions · from £61,500
- Home office extensions · from £17,500
- Conservatory replacement extensions · from £22,000
- Timber frame extensions · from £23,500
Neighbouring areas
Questions about extensions in West Sussex
How much does an extension cost in West Sussex?
With our South East England factor (×1.12), a standard-spec 20 m² single-storey extension is a guide £45,500 to £58,500 including VAT. Prices for every type are linked on this page.
Can I get a price before anyone visits?
Yes. This page shows guide prices adjusted for West Sussex, and the guide-price tool gives a range for your own size and finish in about a minute.
Do you handle building regulations?
Yes. We prepare the drawings and calculations, submit them and book inspections, ending with a completion certificate.
Do you cover all of West Sussex?
Yes, across the whole of West Sussex. Site visits are free and there is no obligation.
Book a free site visit in West Sussex
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.