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 Chapeltown?
In Chapeltown, 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. We start from a UK-wide guide and adjust it for Yorkshire and the Humber, where labour and materials are typically about 7% below 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 |
The main things that change the cost:
- How much of the existing house is opened up
- Roof type and the size of any lantern or roof windows
- Ground conditions and foundation depth
- Glazing: sliding and bifold doors cost more than French doors
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 single-storey extension in Chapeltown?
Approvals for a single-storey extension in Chapeltown follow the rules for 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.
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.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
Handled as part of most single-storey extensions:
- Measured survey and design drawings
- Building control inspections and completion certificate
- Foundations, drainage and any build-over agreement
- Structural calculations for steels and lintels
- Cavity walls, insulation and roof to current building regulations
- Doors, windows and roof glazing installed
How long does it take?
The build itself usually takes 10 to 14 weeks on site for a typical rear extension, after approvals. Before that, surveys, drawings and approvals usually take 6 to 12 weeks, longer if the council asks for changes.
Building in Chapeltown
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.
From S35 outwards, we take on projects throughout Chapeltown and the surrounding parts of South Yorkshire.
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
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about single-storey extensions in Chapeltown
How much does a single-storey extension cost in Chapeltown?
In Chapeltown, 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.
How long does a single-storey extension take in Chapeltown?
Typically 10 to 14 weeks on site for a typical rear extension, after approvals. Design and approvals beforehand usually take 6 to 12 weeks.
Do I need planning permission for a single-storey extension?
Not always. Many small rear extensions are permitted development, within limits on depth, height and how much of the garden is covered. The limits depend on which nation you live in and on protected areas such as conservation areas, and flats or houses whose rights have been removed need an application. We check this at the survey and can apply to the council for formal confirmation.
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.
Can I stay in the house during the build?
Usually yes. We build the shell before opening up the back wall, so the house stays weathertight for most of the job. There will be a few weeks when the kitchen or back room is out of use.
