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 Leicester?
In Leicester, a side return extension typically costs £2,200–£3,150 per m² of floor area, including VAT at 20% (standard rate). For a typical 12 m² project that is roughly £26,500–£38,000. The guide for Leicester reflects typical costs in the East Midlands, roughly 5% below the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (8 m²) | £17,500–£25,000 |
| Typical project (12 m²) | £26,500–£38,000 |
| Larger project (17 m²) | £37,500–£53,500 |
| Rate per m² | £2,200–£3,150 |
The main things that change the cost:
- Steel beams and propping of the back addition
- Party wall surveyor fees
- Access through the house for materials
- Moving drains and soil stacks
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 Leicester?
Approvals for a side return extension in Leicester follow the rules for 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.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
From survey to sign-off, the job normally involves:
- Survey of party walls, drains and the existing back addition
- Building control sign-off
- Floor levelling, heating and electrics
- Drawings and planning or permitted development check
- Glazed or solid roof with insulation
- Foundations and drainage, including any build-over agreement
How long does it take?
Allow 10 to 14 weeks on site. Design and approvals come first and typically take 3 to 4 months, depending on the approval route.
Building in Leicester
The East Midlands has a mix of red-brick terraces, inter-war semis and newer estates, so rear extensions and garage conversions are common projects.
Our Leicester coverage includes postcode districts LE1 and LE19, and we also work in nearby places such as Oadby, Wigston Magna and Earl Shilton.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about side return extensions in Leicester
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.
Will I need a party wall agreement?
Almost certainly in England and Wales, because side returns sit on or near the boundary. Notices must be served before work starts, and a party wall surveyor may be appointed if the neighbour does not consent.
Do you build side return extensions in Leicester?
Yes. We build side return extensions across Leicester, including postcodes LE1 and LE19. Every project starts with a free home visit.
Does a side return extension need planning permission?
It depends on the design and where you live. In England a side return can sometimes be permitted development, but side extensions in conservation areas and on many terraced streets need an application. We check your house’s rights before designing.
How much does a side return extension cost in Leicester?
In Leicester, a side return extension typically costs £2,200–£3,150 per m² of floor area, including VAT at 20% (standard rate). A typical 12 m² project comes to roughly £26,500–£38,000. Your fixed price depends on the survey and drawings.
