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 New Milton?
In New Milton, a single-storey extension typically costs £2,200–£3,250 per m² of floor area, including VAT at 20% (standard rate). For a typical 20 m² project that is roughly £44,000–£65,000. That range is adjusted for the South East, where domestic building work typically costs around 12% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (14 m²) | £31,000–£45,500 |
| Typical project (20 m²) | £44,000–£65,000 |
| Larger project (28 m²) | £61,500–£91,000 |
| Rate per m² | £2,200–£3,250 |
The biggest cost drivers are:
- Kitchen, flooring and finishes, which we can include or leave to you
- How much of the existing house is opened up
- Ground conditions and foundation depth
- Roof type and the size of any lantern or roof windows
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a single-storey extension in New Milton?
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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
From survey to sign-off, the job normally involves:
- Cavity walls, insulation and roof to current building regulations
- Knock-through to the existing house with steel beams
- Measured survey and design drawings
- Building control inspections and completion certificate
- Doors, windows and roof glazing installed
- First and second fix electrics, heating and plastering
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 New Milton
The South East has a broad mix of housing, from Victorian terraces in the towns to post-war semis and newer estates, so extension types vary street by street.
If your home is in New Milton or close by in Christchurch, Bournemouth and Hythe, 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
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about single-storey extensions in New Milton
How long does a single-storey extension take?
Once approvals are in place, a typical rear extension takes 10 to 14 weeks on site. Design and approvals usually take another 6 to 12 weeks beforehand, depending on whether a planning application is needed.
How much does a single-storey extension cost in New Milton?
In New Milton, a single-storey extension typically costs £2,200–£3,250 per m² of floor area, including VAT at 20% (standard rate). A typical 20 m² project comes to roughly £44,000–£65,000. Your fixed price depends on the survey and drawings.
Who approves a single-storey extension in New Milton?
Planning matters in New Milton go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
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.
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.