Single-storey extensions in Barnet

Covering Barnet

Alongside Barnet, we also cover Potters Bar, Borehamwood (3 miles to the west) and Finchley.

Homes in London

Terraced houses dominate many London neighbourhoods, so most projects involve shared walls, narrow access and a party wall process. Conservation areas are widespread, and some boroughs have their own mansard and basement guidance.

What does a single-storey extension involve?

We design the extension around how you use the house: where the light comes from, how the new room joins the old one, and what happens to the drains and the garden. The structure is built in brick or block to match the house, finished with a flat roof and lantern or a pitched roof, then insulated, plastered and handed back ready to decorate.

Measured survey and design drawings
Building control application and inspections
Foundations, drainage and structural steel

How much should I budget for a single-storey extension?

What single-storey extensions typically cost. These are guide ranges; the written quote for your house replaces them.

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?

English projects need planning clearance from the local council, building regulations sign-off from building control, and party wall notices where the work is on or near a shared boundary. We prepare and manage all three.

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. Deeper extensions, up to 6 m or 8 m, need prior approval from the council first.

What can change the price or programme?

Building on or near a shared boundary usually means serving a party wall notice in England and Wales.
Large glazed areas need to meet energy rules, which can shape the size of doors and rooflights.

How does the project run?

Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.

Your questions answered

Do you need to dig up the drains?

Sometimes. If a public sewer runs under the extension, the water company has to agree a build-over or a diversion. We check this at survey stage.

Will the brick match?

We source the closest available match for colour, size and texture and agree a sample panel with you before laying.

Can you visit a house in Barnet to quote?

Yes. After a short call we arrange a site visit to measure up and agree what the design needs to do, then send a written price.

Single-storey extensions near Barnet

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