Side extensions for homes in Eastbourne
Our design and build teams take on side extensions in Eastbourne, from the first measured survey through planning and building control to the finished room.
- Guide price in EastbourneFrom £24,500 inc VAT
- PlanningSingle storey can be permitted development
- Build time10–18 weeks on site
- Postcode districtsBN20, BN21, BN22, BN23, BN24

Planning rules that apply in Eastbourne
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
How much does a side extension cost in Eastbourne?
Prices below are for Eastbourne, using the South East England factor of ×1.12. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Eastbourne: £1,960 to £3,810 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £24,500 – £30,000 | £27,500 – £36,000 | £34,500 – £46,000 |
| 3 m × 6 m 18 m² | £35,000 – £42,500 | £41,000 – £53,500 | £52,000 – £69,000 |
| 3 m × 8 m 24 m² | £47,000 – £56,500 | £55,000 – £71,500 | £69,500 – £91,500 |
Try the guide-price tool to see a range for your own size and finish.
Working in Eastbourne
Our survey diary covers Eastbourne, including BN20, BN21, BN22, BN23, BN24, BN26. We also work in nearby Hailsham (7 miles), Seaford (8 miles), Bexhill-on-Sea (10 miles), Peacehaven (13 miles).
Just over the West Sussex border, Burgess Hill is about 22 miles away. In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
Is a side extension right for your house?
- Detached and semi-detached houses with side land
- Homes needing a utility, study or ground-floor bedroom
- Houses where the rear garden is small
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Your questions about a side extension in Eastbourne
Who do I contract with for a side extension in Eastbourne?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do I need building regulations approval in Eastbourne?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Do you cover all of Eastbourne?
Yes. We cover Eastbourne and the surrounding parts of East Sussex. Site visits are free and there is no obligation.
How much does a side extension cost?
Our guide range is about £1,960 to £3,810 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £41,000 to £53,500 in Eastbourne.
Can I build a side extension without planning permission?
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a planning application.
Book a free site visit in Eastbourne
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.