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 Billingham?
In Billingham, a side return extension typically costs £2,050–£2,950 per m² of floor area, including VAT at 20% (standard rate). For a typical 12 m² project that is roughly £24,500–£35,500. Prices across the North East are typically 10% below the UK average for this kind of work, which is reflected in the range for Billingham. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (8 m²) | £16,500–£23,500 |
| Typical project (12 m²) | £24,500–£35,500 |
| Larger project (17 m²) | £35,000–£50,000 |
| Rate per m² | £2,050–£2,950 |
What moves the price most:
- Steel beams and propping of the back addition
- Access through the house for materials
- Glazed roof specification
- 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 Billingham?
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
Handled as part of most side return extensions:
- Steel beams to remove the side wall
- Survey of party walls, drains and the existing back addition
- Glazed or solid roof with insulation
- Drawings and planning or permitted development check
- Floor levelling, heating and electrics
- Party wall advice and notices
How long does it take?
Expect 10 to 14 weeks on site. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Billingham
The North East has many terraced streets and post-war semis, where rear extensions and loft conversions are popular ways to gain space.
We work across Billingham and neighbouring areas such as Stockton-on-Tees, Middlesbrough and Thornaby-on-Tees. Postcodes we cover in Billingham include TS23.
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 Billingham
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.
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.
Do you build side return extensions in Billingham?
Yes. We build side return extensions across Billingham, including postcodes TS23. Every project starts with a free home visit.
How much does a side return extension cost in Billingham?
In Billingham, a side return extension typically costs £2,050–£2,950 per m² of floor area, including VAT at 20% (standard rate). A typical 12 m² project comes to roughly £24,500–£35,500. 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.
