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 Burnham-on-Sea?
In Burnham-on-Sea, a side return extension typically costs £2,350–£3,350 per m² of floor area, including VAT at 20% (standard rate). For a typical 12 m² project that is roughly £28,000–£40,000. Prices in the South West sit near the national average for this kind of work, and the range for Burnham-on-Sea reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (8 m²) | £19,000–£27,000 |
| Typical project (12 m²) | £28,000–£40,000 |
| Larger project (17 m²) | £40,000–£57,000 |
| Rate per m² | £2,350–£3,350 |
The main things that change the cost:
- Party wall surveyor fees
- Access through the house for materials
- Glazed roof specification
- Moving drains and soil stacks
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a side return extension in Burnham-on-Sea?
The approval route for Burnham-on-Sea 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.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
On a typical side return extension we handle:
- Party wall advice and notices
- Glazed or solid roof with insulation
- Drawings and planning or permitted development check
- Building control sign-off
- Floor levelling, heating and electrics
- Survey of party walls, drains and the existing back addition
How long does it take?
The build itself usually takes 10 to 14 weeks on site. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Burnham-on-Sea
The South West mixes stone and render cottages with post-war and newer estates, and local materials matter more here when matching an extension.
If your home is in Burnham-on-Sea or close by in Weston-super-Mare, Bridgwater and Clevedon, a free home visit is the first step.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 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 Burnham-on-Sea
Do you build side return extensions in Burnham-on-Sea?
Yes. We build side return extensions across Burnham-on-Sea, including postcodes TA8. Every project starts with a free home visit.
How much does a side return extension cost in Burnham-on-Sea?
In Burnham-on-Sea, a side return extension typically costs £2,350–£3,350 per m² of floor area, including VAT at 20% (standard rate). A typical 12 m² project comes to roughly £28,000–£40,000. Your fixed price depends on the survey and drawings.
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.
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.
