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 Wellingborough?
In Wellingborough, 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. Prices across the East Midlands are typically 5% below the UK average for this kind of work, which is reflected in the range for Wellingborough. 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 |
What moves the price most:
- Moving drains and soil stacks
- Access through the house for materials
- Party wall surveyor fees
- Steel beams and propping of the back addition
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 Wellingborough?
Here is how the rules work for a side return extension 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
Handled as part of most side return extensions:
- Steel beams to remove the side wall
- Drawings and planning or permitted development check
- Glazed or solid roof with insulation
- Survey of party walls, drains and the existing back addition
- Floor levelling, heating and electrics
- Party wall advice and notices
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 Wellingborough
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.
Wellingborough sits in Northamptonshire, about 9 miles north-east of Northampton. We cover the whole of Wellingborough, including postcodes NN8.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about side return extensions in Wellingborough
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.
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.
How much does a side return extension cost in Wellingborough?
In Wellingborough, 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.
Do you build side return extensions in Wellingborough?
Yes. We build side return extensions across Wellingborough, including postcodes NN8. Every project starts with a free home visit.
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.