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 Warwickshire?
In Warwickshire, a side return extension typically costs £2,250–£3,200 per m² of floor area, including VAT at 20% (standard rate). For a typical 12 m² project that is roughly £27,000–£38,500. Building costs in the West Midlands are close to the UK average, so the figures for Warwickshire are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (8 m²) | £18,000–£25,500 |
| Typical project (12 m²) | £27,000–£38,500 |
| Larger project (17 m²) | £38,000–£54,500 |
| Rate per m² | £2,250–£3,200 |
The biggest cost drivers are:
- Access through the house for materials
- Steel beams and propping of the back addition
- Glazed roof specification
- 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 Warwickshire?
Whether you need planning permission depends on your house and its location 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
The work we manage on a side return extension:
- Floor levelling, heating and electrics
- Steel beams to remove the side wall
- Glazed or solid roof with insulation
- Party wall advice and notices
- Drawings and planning or permitted development check
- Survey of party walls, drains and the existing back addition
How long does it take?
Allow 10 to 14 weeks on site. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Warwickshire
Across the West Midlands, inter-war and post-war semis make up much of the housing, giving good scope for two-storey side extensions and hip-to-gable lofts.
Towns we cover in Warwickshire include Nuneaton, Rugby, Leamington Spa, Warwick, Bedworth and Stratford-upon-Avon.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 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 Warwickshire
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.
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 Warwickshire?
Yes. We build side return extensions across Warwickshire, including postcodes B46, B49, B50, B76 and B78. Every project starts with a free home visit.
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 Warwickshire?
In Warwickshire, a side return extension typically costs £2,250–£3,200 per m² of floor area, including VAT at 20% (standard rate). A typical 12 m² project comes to roughly £27,000–£38,500. Your fixed price depends on the survey and drawings.
