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 Gloucester?
In Gloucester, a single-storey extension typically costs £2,000–£2,950 per m² of floor area, including VAT at 20% (standard rate). For a typical 20 m² project that is roughly £40,000–£59,000. Building costs in the South West are close to the UK average, so the figures for Gloucester are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (14 m²) | £28,000–£41,500 |
| Typical project (20 m²) | £40,000–£59,000 |
| Larger project (28 m²) | £56,000–£82,500 |
| Rate per m² | £2,000–£2,950 |
Your quote will depend mainly on:
- How much of the existing house is opened up
- Glazing: sliding and bifold doors cost more than French doors
- Ground conditions and foundation depth
- 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 Gloucester?
Whether you need planning permission depends on your house and its location 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:
- Foundations, drainage and any build-over agreement
- First and second fix electrics, heating and plastering
- Structural calculations for steels and lintels
- Doors, windows and roof glazing installed
- Cavity walls, insulation and roof to current building regulations
- Measured survey and design drawings
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 Gloucester
In parts of the South West, protected landscapes and conservation areas shape what can be built, so materials and roof forms are chosen carefully.
If your home is in Gloucester or close by in Cheltenham, Stroud and Tewkesbury, a free home visit is the first step.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 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 Gloucester
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.
How much does a single-storey extension cost in Gloucester?
In Gloucester, a single-storey extension typically costs £2,000–£2,950 per m² of floor area, including VAT at 20% (standard rate). A typical 20 m² project comes to roughly £40,000–£59,000. Your fixed price depends on the survey and drawings.
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 Gloucester?
Typically 10 to 14 weeks on site for a typical rear extension, after approvals. Design and approvals beforehand usually take 6 to 12 weeks.