Side return extensions in London.
Fulham · SW6 · a kitchen under a long rooflight, steel glazing to the gardenCompleted work, photograph
A side return fills the narrow passage beside a period house. The kitchen gains width and light.
A narrow passage becomes the widest room.
A side return extension fills the passage beside the rear of a period house. We are NU Projects, design and build in Fulham SW6 since 2010. A side return extension typically runs £140k to £220k. Call 020 7731 6841, and a budget estimate typically follows within seven days.
Many Victorian and Edwardian houses have a narrow passage beside the rear wing. A side return extension builds over it.
The kitchen gains width, often enough for an island and a table. A wraparound adds a rear extension as well.
Daylight is the design question. Roof glazing along the side can light the middle of the house.
The side wall comes out, so steel carries the house above. The engineer designs it, and we check it on site.
Building on or near the boundary usually engages the Party Wall Act. We serve the notices early.
The existing ground floor changes too. We price the new area and the reworked rooms separately.
What the work includes
- Side return and wraparound extensions
- Planning or permitted development, checked for your address
- Steel, foundations and drainage designed with the engineer
- Roof glazing placed for daylight, heat and shading
- Party wall notices served before work starts
- Kitchen, joinery and finishes in the same contract
- Sources
- Planning Portal, extensions, GOV.UK permitted development technical guidance. Read on 21 October 2026. Rules for England.
- What it costs
- See a range in a minute. Then send us the address for a proper number. Open the calculator
- Where we work
- Fulham, Chelsea, Kensington, Knightsbridge, Belgravia, Mayfair, Notting Hill and Holland Park, Chiswick, Wandsworth, Putney and Barnes, Hampstead and St John’s Wood, Weybridge, Cobham and Oxshott, South Kensington, Marylebone, Bayswater and Maida Vale, Pimlico and Westminster, Battersea and Clapham, Richmond, Twickenham and East Sheen, Islington, Highgate and Primrose Hill, Greenwich, Dulwich, Camden, Wimbledon, Bermondsey, Brixton, Ealing, Acton, Hammersmith and Brook Green, Earl’s Court, Queen’s Park and Kensal Rise, Fitzrovia and Bloomsbury
Daylight is planned before the glazing. Then the kitchen is drawn around it.
From the passage to the new kitchen.
- 01
The passage and the boundary
A measured survey of the side, the drains and the neighbour’s wall.
- 02
Daylight first
Roof glazing placed before the kitchen layout is fixed.
- 03
Structure
Steel to replace the side wall, designed by the engineer.
- 04
Consents and notices
Permitted development or planning, building control and party wall notices.
- 05
The cost plan
Priced line by line from the drawings, open book.
- 06
Build and handover
A weekly report with photographs, then a defects period and aftercare.
Permitted development, in plain terms.
- 01
Single storey only
Under permitted development, a side extension can only be one storey.
- 02
Four metres high
It cannot exceed four metres in height.
- 03
Half the width
It can be up to half the width of the original house.
- 04
Conservation areas
In a conservation area, every side extension needs householder planning permission.
- 05
Near the boundary
Within two metres of the boundary, the eaves cannot exceed three metres.
- 06
Matching materials
Exterior materials must look similar to the existing house.
- 07
Earlier extensions count
The limits apply to the total, including any earlier extensions.
- 08
Article 4 directions
A council direction can remove permitted development rights altogether.
- 09
Houses only
These rights apply to houses, not to flats or maisonettes.
What a side return costs in London.
£140k to £220kSide return extension. A project total, from our 2026 cost guide.
£200k to £320kWraparound extension. A project total, from our 2026 cost guide.
Glazing, structure and the kitchen move the figure most.
Reworking the existing rooms is priced as its own line.
Professional fees, statutory costs, party wall, contingency and VAT are separate. Ranges are guide prices, not fixed quotations.
A kitchen extension we built in Fulham.
House and kitchen extensionsSide return or rear extension, a guideParty wall agreements explained
What owners ask before a side return.
Further reading, from the journal
Is a side-return extension right for my house?
We test the gain in usable width against daylight, circulation and garden access. Extending to the boundary is not always the right answer for every home.
A side return extension typically runs £140k to £220k.
Can I have a large rooflight or glass roof?
Glazing needs coordination for structure, heat gain, shading and maintenance. It also needs to keep the room below comfortable.
More glass does not always produce a better living space.
Can I have a level threshold into the garden?
A near-level transition needs coordinated internal and external levels, drainage and waterproofing. We resolve this technically, not just from a drawing or a visual.
What if a public sewer runs beneath the proposed extension?
We check the sewer position and ownership before design proceeds. Thames Water advises agreement is often needed within three metres of a public sewer. The same applies within one metre of a public lateral drain. Planning permission does not provide that consent.
How much does a side return extension cost in London?
Our 2026 cost guide puts a side return extension at £140k to £220k.
That is a project total, before fees, contingency and VAT.
Do I need planning permission for a side return extension?
Not always. A single storey side extension can be permitted development, within set limits.
In a conservation area, every side extension needs planning permission.
We check the route against your address before design starts.
Is a side return or a wraparound better?
A side return widens the kitchen. A wraparound also extends it into the garden.
Our 2026 cost guide puts a wraparound at £200k to £320k.
We draw and price both, so you can compare.
Tell us about the house.
Your name and one way to reply are enough. It goes straight to the studio.
- Already have an architect or designer? We build to their design. Working with your designer