Single-storey extensions in Chelsea

Covering Chelsea

Chelsea is about 2 miles south-west of London. We also cover Battersea (1 miles to the south-east), Fulham and Notting Hill.

Homes in London

London projects often mean working on period terraces with neighbours on both sides, tight access through the house and conservation area controls, so careful planning and party wall work matter as much as the build.

What is included in a single-storey extension in Chelsea?

A single-storey extension adds one level of new floor space to the back or side of a house, usually to open up a kitchen, dining or family room. It is the most common way to gain space without moving, and many can be built without a planning application.

Measured survey and design drawings
Planning or lawful development certificate where needed
Brickwork, roof, glazing and insulation

How much does a single-storey extension cost in Chelsea?

Indicative costs for single-storey extensions. London and the South East usually sit towards the top of each range.

Single-storey extensions	Guide price incl. VAT
Standard specification	£2,600 to £3,000 per m²
Good specification	£3,000 to £3,500 per m²
High specification	£3,500 to £4,000 per m²

What approvals does a single-storey extension need in England?

In England we deal with the council’s planning team for permission or a lawful development certificate, with building control (the council or a registered building control approver) for inspections, and with neighbours under the Party Wall etc. Act 1996 where it applies.

In England a single-storey rear extension can often go ahead under permitted development: up to 3 m deep on an attached house or 4 m on a detached one, no higher than 4 m, with eaves no higher than 3 m within 2 m of a boundary.

What should Chelsea homeowners check first?

Building on or near a shared boundary usually means serving a party wall notice in England and Wales.
Kitchens and doors have long lead times, so we order them early.

What are the steps?

Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
Construction and completion. One site lead co-ordinates every trade through to the building control certificate.

Single-storey extensions: common questions

How much does a single-storey extension cost?

Most single-storey extensions cost about £2,600 to £4,000 per square metre including VAT, depending on specification, glazing and ground conditions. We give a fixed price in writing for the agreed specification after the survey.

Do I need planning permission for a single-storey extension?

Often not in England, if the extension stays within permitted development limits: 3 m deep on an attached house or 4 m on a detached house, and no higher than 4 m. Larger ones need prior approval or a planning application. Wales, Scotland and Northern Ireland have their own rules.

Do you work in Chelsea?

Yes. Chelsea is within our coverage for single-storey extensions, along with nearby Battersea and Fulham.

Single-storey extensions in nearby towns

Learn more about single-storey extensions, or see every project we cover in Chelsea.