Single-storey extensions in Finchley

Covering Finchley

Finchley is about 7 miles north-west of London. We also cover Muswell Hill (2 miles to the east), Cricklewood and Kilburn.

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 goes into a single-storey extension?

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
Planning or lawful development certificate where needed
Foundations, drainage and structural steel

What is the guide price for a single-storey extension in Finchley?

Use these ranges to budget for single-storey extensions; the survey turns them into a fixed price for the agreed specification.

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

Planning and building rules in Finchley

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

What can affect a single-storey extension?

Drains under the footprint may need diverting or a build-over agreement with the water company.
Large glazed areas need to meet energy rules, which can shape the size of doors and rooflights.

How does the project run?

Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
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.
We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.

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 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.

Do you work in Finchley?

Yes. Finchley is within our coverage for single-storey extensions, along with nearby Muswell Hill and Cricklewood.

Single-storey extensions near Finchley

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