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 Whitley Bay?
In Whitley Bay, a single-storey extension typically costs £1,750–£2,600 per m² of floor area, including VAT at 20% (standard rate). For a typical 20 m² project that is roughly £35,000–£52,000. Building costs in the North East run about 10% below the UK average, and the figures for Whitley Bay are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (14 m²) | £24,500–£36,500 |
| Typical project (20 m²) | £35,000–£52,000 |
| Larger project (28 m²) | £49,000–£73,000 |
| Rate per m² | £1,750–£2,600 |
Your quote will depend mainly on:
- How much of the existing house is opened up
- Kitchen, flooring and finishes, which we can include or leave to you
- 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 Whitley Bay?
The approval route for Whitley Bay is set by planning law 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.
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 single-storey extension we handle:
- Structural calculations for steels and lintels
- Building control inspections and completion certificate
- Foundations, drainage and any build-over agreement
- Doors, windows and roof glazing installed
- First and second fix electrics, heating and plastering
- Cavity walls, insulation and roof to current building regulations
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 Whitley Bay
The North East has many terraced streets and post-war semis, where rear extensions and loft conversions are popular ways to gain space.
Projects in Whitley Bay (NE26) are surveyed in person before we quote, so the price reflects your actual property.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 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
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about single-storey extensions in Whitley Bay
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.
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.
How long does a single-storey extension take in Whitley Bay?
Typically 10 to 14 weeks on site for a typical rear extension, after approvals. Design and approvals beforehand usually take 6 to 12 weeks.
How much does a single-storey extension cost in Whitley Bay?
In Whitley Bay, a single-storey extension typically costs £1,750–£2,600 per m² of floor area, including VAT at 20% (standard rate). A typical 20 m² project comes to roughly £35,000–£52,000. Your fixed price depends on the survey and drawings.
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.
