Friern Barnet wraparound extensions, designed and built
A wraparound extension in Friern Barnet starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in Friern BarnetFrom £46,500 inc VAT
- PlanningUsually a householder application
- Build time14–20 weeks on site
- Postcode districtsN2, N3, N10, N11, N12
How much does a wraparound extension cost in Friern Barnet?
For Friern Barnet we adjust our national guide rates by ×1.3, the factor we use for London. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Friern Barnet: £2,600 to £4,810 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Compact L-shape 18 m² | £46,500 – £56,500 | £53,500 – £68,000 | £67,500 – £87,000 |
| Medium L-shape 25 m² | £65,000 – £78,000 | £74,500 – £94,500 | £94,000 – £120,500 |
| Large L-shape 32 m² | £83,000 – £100,000 | £95,500 – £121,000 | £120,500 – £154,000 |
For a figure based on your own dimensions, use our guide-price tool.
When a wraparound extension makes sense
- Semi-detached houses with a side passage
- Terraced houses that want the largest ground floor possible
- Families who want kitchen, dining and living in one space
Do I need planning permission in Friern Barnet?
In England a wraparound extension is assessed as both a side and a rear extension, and the combination usually falls outside permitted development, so most need a householder planning application (£548 from 1 April 2026).
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
Local to Friern Barnet
Site visits are available across Friern Barnet (N2, N3, N10, N11, N12, N20). Neighbouring towns we cover include Muswell Hill (2 miles), Finchley (2 miles), Wood Green (2 miles), Palmers Green (2 miles).
London's housing is dominated by Victorian and Edwardian terraces, many with a rear outrigger and a side return, and 1930s semis in the outer boroughs. Conservation areas are common, so the planning check comes first.
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
We visit your Friern Barnet home, measure up, talk through what you want and check the planning position.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Your questions about a wraparound extension in Friern Barnet
Do you cover all of Friern Barnet?
Yes. We cover Friern Barnet and the surrounding parts of Greater London. Site visits are free and there is no obligation.
Will my neighbours in Friern Barnet be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
How long does a wraparound extension take to build in Friern Barnet?
On site, typically 14 to 20 weeks once approvals are in place. Before that, allow 8–16 weeks design and approvals.
Is a wraparound better than a side return alone?
It adds far more space, but costs more and needs planning permission more often. Our comparison guide sets the two side by side.
How much does a wraparound extension cost?
Our guide range is about £2,600 to £4,810 per m² including VAT. A 25 m² standard-spec wraparound typically lands around £74,500 to £94,500 in Friern Barnet before design and council fees.
Book a free site visit in Friern Barnet
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.