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 Aylesbury?
In Aylesbury, a side return extension typically costs £2,600–£3,700 per m² of floor area, including VAT at 20% (standard rate). For a typical 12 m² project that is roughly £31,000–£44,500. Building costs in the South East run about 12% above the UK average, and the figures for Aylesbury are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (8 m²) | £21,000–£29,500 |
| Typical project (12 m²) | £31,000–£44,500 |
| Larger project (17 m²) | £44,000–£63,000 |
| Rate per m² | £2,600–£3,700 |
What moves the price most:
- Glazed roof specification
- Party wall surveyor fees
- Moving drains and soil stacks
- Steel beams and propping of the back addition
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a side return extension in Aylesbury?
The approval route for Aylesbury 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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
On a typical side return extension we handle:
- Drawings and planning or permitted development check
- Foundations and drainage, including any build-over agreement
- Party wall advice and notices
- Glazed or solid roof with insulation
- Floor levelling, heating and electrics
- Survey of party walls, drains and the existing back addition
How long does it take?
Allow 10 to 14 weeks on site. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Aylesbury
The South East has a broad mix of housing, from Victorian terraces in the towns to post-war semis and newer estates, so extension types vary street by street.
We work across Aylesbury and neighbouring areas such as Leighton Buzzard, Berkhamsted and Chesham. Postcodes we cover in Aylesbury include HP19 and HP20.
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 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 Aylesbury
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.
Is a glass roof too hot or cold?
Modern solar-control double or triple glazing reduces glare and heat loss. Building regulations also limit how much glazing you can have unless the design shows it performs well enough.
Do you build side return extensions in Aylesbury?
Yes. We build side return extensions across Aylesbury, including postcodes HP19 and HP20. 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 Aylesbury?
In Aylesbury, a side return extension typically costs £2,600–£3,700 per m² of floor area, including VAT at 20% (standard rate). A typical 12 m² project comes to roughly £31,000–£44,500. Your fixed price depends on the survey and drawings.