What is a side return extension?

A side return extension fills the narrow passage that runs alongside the back addition of many Victorian and Edwardian terraced houses. It widens a galley kitchen into a proper kitchen-diner, usually with a sloping glazed roof to keep the room bright.
How much does a side return extension cost in Selby?
In Selby, a side return extension typically costs £2,150–£3,050 per m² of floor area, including VAT at 20% (standard rate). For a typical 12 m² project that is roughly £26,000–£36,500. That range is adjusted for Yorkshire and the Humber, where domestic building work typically costs around 7% below the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (8 m²) | £17,000–£24,500 |
| Typical project (12 m²) | £26,000–£36,500 |
| Larger project (17 m²) | £36,500–£52,000 |
| Rate per m² | £2,150–£3,050 |
The main things that change the cost:
- Length of the side return
- Access through the house for materials
- Glazed roof specification
- Party wall surveyor fees
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a side return extension in Selby?
The approval route for Selby is set by planning law in England. In England a side return infill is treated as a side extension. It may be permitted development if it is single-storey, no more than 4 metres high and no wider than half the original house, but not in a conservation area. Because side returns sit on the boundary, party wall notices are almost always needed.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
We check this for your address before design work starts, so there are no surprises later.
What we handle
The work we manage on a side return extension:
- Survey of party walls, drains and the existing back addition
- Glazed or solid roof with insulation
- Floor levelling, heating and electrics
- Foundations and drainage, including any build-over agreement
- Party wall advice and notices
- Building control sign-off
How long does it take?
Expect 10 to 14 weeks on site. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Selby
Yorkshire and the Humber has stone and brick terraces as well as inter-war and newer estates, so materials matching is an early design question.
We work across Selby and neighbouring areas such as Goole, Pontefract and York. Postcodes we cover in Selby include YO8.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about side return extensions in Selby
How do you get materials in?
Mid-terrace houses often have no rear access, so materials come through the house. We protect floors and plan deliveries carefully.
Can I stay in the house?
Usually, though the kitchen will be out of action for several weeks. We plan a temporary kitchen area where possible.
How long does a side return extension take in Selby?
Typically 10 to 14 weeks on site. Design and approvals beforehand usually take 3 to 4 months.
How much does a side return extension cost in Selby?
In Selby, a side return extension typically costs £2,150–£3,050 per m² of floor area, including VAT at 20% (standard rate). A typical 12 m² project comes to roughly £26,000–£36,500. Your fixed price depends on the survey and drawings.
How much space does a side return add?
Typically 1.5 to 2.5 metres of width along the back addition. It often turns a narrow galley kitchen into a family kitchen-diner.
