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 Feltham?
In Feltham, a side return extension typically costs £3,000–£4,300 per m² of floor area, including VAT at 20% (standard rate). For a typical 12 m² project that is roughly £36,000–£51,500. The guide for Feltham reflects typical costs in London, roughly 30% above the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (8 m²) | £24,000–£34,500 |
| Typical project (12 m²) | £36,000–£51,500 |
| Larger project (17 m²) | £51,000–£73,000 |
| Rate per m² | £3,000–£4,300 |
The main things that change the cost:
- Length of the side return
- Access through the house for materials
- Steel beams and propping of the back addition
- Glazed roof specification
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 Feltham?
Before anything is built in Feltham, 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.
We check this for your address before design work starts, so there are no surprises later.
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
- Survey of party walls, drains and the existing back addition
- Foundations and drainage, including any build-over agreement
- Party wall advice and notices
- Floor levelling, heating and electrics
How long does it take?
Expect 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 Feltham
Many London boroughs have conservation areas and detailed design guides, so early design advice saves time at the planning stage.
Feltham sits in Greater London, about 13 miles west of central London. We cover the whole of Feltham, including postcodes TW13.
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
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about side return extensions in Feltham
Do you build side return extensions in Feltham?
Yes. We build side return extensions across Feltham, including postcodes TW13. Every project starts with a free home visit.
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.
How much does a side return extension cost in Feltham?
In Feltham, a side return extension typically costs £3,000–£4,300 per m² of floor area, including VAT at 20% (standard rate). A typical 12 m² project comes to roughly £36,000–£51,500. Your fixed price depends on the survey and drawings.
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.