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 Grantham?
In Grantham, a side return extension typically costs £2,200–£3,150 per m² of floor area, including VAT at 20% (standard rate). For a typical 12 m² project that is roughly £26,500–£38,000. Prices across the East Midlands are typically 5% below the UK average for this kind of work, which is reflected in the range for Grantham. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (8 m²) | £17,500–£25,000 |
| Typical project (12 m²) | £26,500–£38,000 |
| Larger project (17 m²) | £37,500–£53,500 |
| Rate per m² | £2,200–£3,150 |
The biggest cost drivers are:
- Length of the side return
- Party wall surveyor fees
- Access through the house for materials
- Steel beams and propping of the back addition
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 Grantham?
Approvals for a side return extension in Grantham 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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
From survey to sign-off, the job normally involves:
- Survey of party walls, drains and the existing back addition
- Foundations and drainage, including any build-over agreement
- Floor levelling, heating and electrics
- Glazed or solid roof with insulation
- Drawings and planning or permitted development check
- Steel beams to remove the side wall
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 Grantham
In the East Midlands, many estates built since the 1960s have integral garages that convert well into a study or bedroom.
If your home is in Grantham or close by in Newark on Trent, Melton Mowbray and Oakham, 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
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 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 Grantham
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 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.
Do you build side return extensions in Grantham?
Yes. We build side return extensions across Grantham, including postcodes NG31. Every project starts with a free home visit.
How much does a side return extension cost in Grantham?
In Grantham, a side return extension typically costs £2,200–£3,150 per m² of floor area, including VAT at 20% (standard rate). A typical 12 m² project comes to roughly £26,500–£38,000. Your fixed price depends on the survey and drawings.