What is a single-storey extension?
A single-storey extension is a ground-floor addition, usually at the rear of a house, that enlarges a kitchen, living or dining space. Most are built with cavity walls on concrete foundations and finished with a flat roof and roof lantern or a pitched tiled roof.
How much does a single-storey extension cost in Selby?
In Selby, a single-storey extension typically costs £1,800–£2,700 per m² of floor area, including VAT at 20% (standard rate). For a typical 20 m² project that is roughly £36,000–£54,000. That range is adjusted for Yorkshire and the Humber, where domestic building work typically costs around 7% below the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (14 m²) | £25,000–£38,000 |
| Typical project (20 m²) | £36,000–£54,000 |
| Larger project (28 m²) | £50,500–£75,500 |
| Rate per m² | £1,800–£2,700 |
What moves the price most:
- Ground conditions and foundation depth
- Kitchen, flooring and finishes, which we can include or leave to you
- How much of the existing house is opened up
- Floor area and the length of new wall
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 single-storey extension in Selby?
Here is how the rules work for a single-storey extension in England. In England a single-storey rear extension is often permitted development: broadly up to 3 metres deep on a semi-detached or terraced house and 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary, and covering no more than half the garden. The larger home extension scheme allows up to 6 or 8 metres if you notify the council first and neighbours have a chance to comment. In conservation areas, National Parks and National Landscapes the larger home extension route, side extensions and cladding are not permitted development. Flats and houses whose rights have been removed need a planning application, and listed buildings need listed building consent.
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
The work we manage on a single-storey extension:
- Doors, windows and roof glazing installed
- Structural calculations for steels and lintels
- Building control inspections and completion certificate
- Cavity walls, insulation and roof to current building regulations
- Knock-through to the existing house with steel beams
- Foundations, drainage and any build-over agreement
How long does it take?
Expect 10 to 14 weeks on site for a typical rear extension, after approvals. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in Selby
Yorkshire and the Humber has stone and brick terraces as well as inter-war and newer estates, so materials matching is an early design question.
If your home is in Selby or close by in Goole, Pontefract and York, a free home visit is the first step.
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
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 handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about single-storey extensions in Selby
How much does a single-storey extension cost in Selby?
In Selby, a single-storey extension typically costs £1,800–£2,700 per m² of floor area, including VAT at 20% (standard rate). A typical 20 m² project comes to roughly £36,000–£54,000. Your fixed price depends on the survey and drawings.
Do I need a party wall agreement?
If you are in England or Wales and the work involves a shared wall, building on the boundary or digging foundations close to a neighbour, the Party Wall etc. Act 1996 applies and notices must be served before work starts. We advise on this at the design stage.
What is a build-over agreement?
If a public sewer runs within 3 metres of the extension, the water company normally has to agree to the work before it starts. We check sewer records during design and apply where needed.
Who approves a single-storey extension in Selby?
Planning matters in Selby go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
Is VAT charged on an extension?
Yes. Building work on an existing home is standard-rated, so VAT at 20% applies. Our guide prices include it.