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 Newport, Isle of Wight?
In Newport, 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. Island and remote projects usually cost more than this guide because of shipping, travel and accommodation. 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:
- How much of the existing house is opened up
- Roof type and the size of any lantern or roof windows
- Glazing: sliding and bifold doors cost more than French doors
- Kitchen, flooring and finishes, which we can include or leave to you
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 Newport, Isle of Wight?
Approvals for a single-storey extension in Newport 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.
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
Handled as part of most single-storey extensions:
- Measured survey and design drawings
- Structural calculations for steels and lintels
- Doors, windows and roof glazing installed
- Cavity walls, insulation and roof to current building regulations
- Knock-through to the existing house with steel beams
- Foundations, drainage and any build-over agreement
How long does it take?
Allow 10 to 14 weeks on site for a typical rear extension, after approvals. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in Newport, Isle of Wight
Commuter towns across the South East have many 1930s and post-war semis that suit rear extensions and hip-to-gable loft conversions.
Projects in Newport are taken on by arrangement. We confirm availability first, and shipping, travel and accommodation costs are shown separately in the quote.
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 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 Newport, Isle of Wight
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.
Do you build single-storey extensions in Newport?
Yes. We build single-storey extensions across Newport, including postcodes PO30. Every project starts with a free home visit.
How much does a single-storey extension cost in Newport?
In Newport, 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.
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.
