Lancing single-storey extensions, designed and built
Thinking about a single-storey extension for your Lancing home? Start with a free site visit: we measure up, check what the council will allow and give you honest guide figures on the day.
- Guide price in LancingFrom £23,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time10–16 weeks on site
- Postcode districtsBN15

Single-storey extension prices in Lancing
For Lancing we adjust our national guide rates by ×1.12, the factor we use for South East England. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Lancing: £1,960 to £3,810 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £23,500 – £28,000 | £27,500 – £35,000 | £34,500 – £46,000 |
| 4 m × 5 m 20 m² | £39,000 – £46,000 | £45,500 – £58,500 | £58,000 – £76,500 |
| 5 m × 6 m 30 m² | £58,500 – £69,000 | £68,500 – £87,500 | £87,000 – £114,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
Covering Lancing
We cover Lancing and the postcode districts BN15. Neighbouring towns we cover include Shoreham-by-Sea (2 miles), Worthing (2 miles), Littlehampton (10 miles), Burgess Hill (12 miles).
In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
What we take care of
- Walls, steel beams and the new opening into the house
- Doors, windows, insulation, plastering and first fix to finish
- Flat or pitched roof, rooflights or lantern
- Measured survey and design
Planning rules that apply in Lancing
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
Our process, step by step
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
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
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions people ask about single-storey extensions
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Lancing, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do I need building regulations approval in Lancing?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Do you cover all of Lancing?
Yes. We cover Lancing and the surrounding parts of West Sussex. Site visits are free and there is no obligation.
How deep can a single-storey rear extension be without planning permission?
In England, up to 3 m beyond the original rear wall on a semi-detached or terraced house and 4 m on a detached house, within height and boundary limits. Through the larger home extension prior approval scheme those depths rise to 6 m and 8 m. Wales, Scotland and Northern Ireland use their own rules, which we check for your address.
Flat roof or pitched roof?
Flat roofs give more headroom inside and suit lanterns and rooflights; pitched roofs can blend better with older houses. Both meet building regulations when built properly. See our flat roof and pitched roof pages for the details.
Book a free site visit in Lancing
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.