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 Hammersmith?
In Hammersmith, 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. That range is adjusted for London, where domestic building work typically costs around 30% above the national average. 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:
- Access through the house for materials
- Glazed roof specification
- Steel beams and propping of the back addition
- Party wall surveyor fees
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 Hammersmith?
Approvals for a side return extension in Hammersmith follow the rules for 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:
- Drawings and planning or permitted development check
- Foundations and drainage, including any build-over agreement
- Glazed or solid roof with insulation
- Survey of party walls, drains and the existing back addition
- Building control sign-off
- Party wall advice and notices
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 Hammersmith
Victorian and Edwardian terraces dominate many London streets, which is why side return, wraparound and mansard projects are so common here.
Our Hammersmith coverage includes postcode districts W6 and W14, and we also work in nearby places such as Chiswick, Fulham and Barnes.
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 pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about side return extensions in Hammersmith
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 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.
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.
Do you build side return extensions in Hammersmith?
Yes. We build side return extensions across Hammersmith, including postcodes W6 and W14. Every project starts with a free home visit.
How much does a side return extension cost in Hammersmith?
In Hammersmith, 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.