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 Derbyshire?
In Derbyshire, 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 Derbyshire. 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 biggest cost drivers are:
- Access through the house for materials
- Glazed roof specification
- Steel beams and propping of the back addition
- Moving drains and soil stacks
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a side return extension in Derbyshire?
Before anything is built in Derbyshire, we confirm which approvals apply 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.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
Handled as part of most side return extensions:
- Building control sign-off
- Drawings and planning or permitted development check
- Party wall advice and notices
- Foundations and drainage, including any build-over agreement
- Glazed or solid roof with insulation
- Survey of party walls, drains and the existing back addition
How long does it take?
Build time is typically 10 to 14 weeks on site. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Derbyshire
In the East Midlands, many estates built since the 1960s have integral garages that convert well into a study or bedroom.
Towns we cover in Derbyshire include Derby, Chesterfield, Long Eaton, Ilkeston, Swadlincote and Staveley.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about side return extensions in Derbyshire
Who approves a side return extension in Derbyshire?
Planning matters in Derbyshire go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
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 does a side return extension cost in Derbyshire?
In Derbyshire, 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.
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.
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.