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 Bishop Auckland?
In Bishop Auckland, 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. That range is adjusted for the North East, where domestic building work typically costs around 10% below the national average. 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 |
The biggest cost drivers are:
- Roof type and the size of any lantern or roof windows
- Ground conditions and foundation depth
- Floor area and the length of new wall
- Kitchen, flooring and finishes, which we can include or leave to you
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 single-storey extension in Bishop Auckland?
Before anything is built in Bishop Auckland, we confirm which approvals apply 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.
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.
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:
- Structural calculations for steels and lintels
- Knock-through to the existing house with steel beams
- Building control inspections and completion certificate
- First and second fix electrics, heating and plastering
- Measured survey and design drawings
- Foundations, drainage and any build-over agreement
How long does it take?
Build time is typically 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 Bishop Auckland
The North East has many terraced streets and post-war semis, where rear extensions and loft conversions are popular ways to gain space.
If your home is in Bishop Auckland or close by in Newton Aycliffe, Durham and Darlington, 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
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
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about single-storey extensions in Bishop Auckland
How long does a single-storey extension take in Bishop Auckland?
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 Bishop Auckland?
In Bishop Auckland, 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.
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.
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.