Side return extensions in Brighton
A side return extension in Brighton starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in BrightonFrom £20,000 inc VAT
- PlanningOften permitted development; party wall notice usual
- Build time10–14 weeks on site
- Postcode districtsBN1, BN2, BN3, BN41

How much does a side return extension cost in Brighton?
Labour and material costs vary across the UK, so for Brighton we use our South East England factor (×1.12). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Brighton: £2,350 to £4,260 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 1.8 m × 4.5 m 8 m² | £20,000 – £24,000 | £21,500 – £27,000 | £26,500 – £34,500 |
| 2 m × 5.5 m 11 m² | £25,500 – £31,000 | £29,500 – £37,000 | £36,500 – £47,000 |
| 2.2 m × 7 m 15 m² | £35,000 – £42,500 | £40,000 – £50,500 | £50,000 – £64,000 |
For a figure based on your own dimensions, use our guide-price tool.
Planning and approvals in Brighton
In England a single-storey side return infill is often permitted development if it stays within the height limits and is no wider than half the width of the original house. Conservation areas, listed buildings and flats always need an application, and the boundary wall usually brings in the Party Wall Act.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
Is a side return extension right for your house?
- Narrow galley kitchens
- Victorian and Edwardian terraces with a rear outrigger
- Homes where the garden is too small to lose much depth
Light is the design problem. A side return can make the middle of the house darker if the roof is solid, so we model the daylight and usually recommend a glazed slope or a run of rooflights along the boundary edge.
Extensions in and around Brighton
Site visits are available across Brighton (BN1, BN2, BN3, BN41). We also work in nearby Hove (1 mile), Portslade (3 miles), Peacehaven (6 miles), Seaford (11 miles).
Just over the West Sussex border, Shoreham-by-Sea is about 6 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.
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
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
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Common questions in Brighton
Do you cover all of Brighton?
Yes. We cover Brighton and the surrounding parts of East Sussex. Site visits are free and there is no obligation.
Who do I contract with for a side return extension in Brighton?
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.
How long does a side return extension take to build in Brighton?
On site, typically 10 to 14 weeks once approvals are in place. Before that, allow 6–12 weeks design and approvals.
Do side return extensions need planning permission?
In England many single-storey side returns fit within permitted development if they stay within the height limits and are no wider than half the width of the original house. Conservation areas, listed buildings and flats need an application. Other UK nations have their own rules, which we check.
Can I combine a side return with a rear extension?
Yes. That combination is a wraparound extension, which adds the most space to a terraced house.
Book a free site visit in Brighton
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.