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 Southport?
In Southport, a side return extension typically costs £2,150–£3,100 per m² of floor area, including VAT at 20% (standard rate). For a typical 12 m² project that is roughly £26,000–£37,000. That range is adjusted for the North West, where domestic building work typically costs around 6% below the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (8 m²) | £17,000–£25,000 |
| Typical project (12 m²) | £26,000–£37,000 |
| Larger project (17 m²) | £36,500–£52,500 |
| Rate per m² | £2,150–£3,100 |
The main things that change the cost:
- Length of the side return
- Steel beams and propping of the back addition
- Access through the house for materials
- 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 Southport?
The approval route for Southport is set by planning law 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.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
From survey to sign-off, the job normally involves:
- Survey of party walls, drains and the existing back addition
- Party wall advice and notices
- Glazed or solid roof with insulation
- Building control sign-off
- Drawings and planning or permitted development check
- Floor levelling, heating and electrics
How long does it take?
The build itself usually takes 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 Southport
The North West has many brick terraces and inter-war semis, where kitchen extensions and dormer loft conversions add space without moving.
From PR8 outwards, we take on projects throughout Southport and the surrounding parts of Merseyside.
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 pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 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 Southport
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 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.
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 does a side return extension cost in Southport?
In Southport, a side return extension typically costs £2,150–£3,100 per m² of floor area, including VAT at 20% (standard rate). A typical 12 m² project comes to roughly £26,000–£37,000. Your fixed price depends on the survey and drawings.
How long does a side return extension take in Southport?
Typically 10 to 14 weeks on site. Design and approvals beforehand usually take 3 to 4 months.