Friern Barnet, Greater London
Two-storey rear extension in Friern Barnet
For homes in Friern Barnet, a two-storey rear extension is often the simplest way to gain space without moving. A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. We take it from survey to completion certificate.
We cover Friern Barnet (N11, N12 and N20) as part of our Greater London work. In Greater London we check the neighbours' rear windows first, because the upper floor is where most two-storey schemes win or lose planning.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a two-storey rear extension cost in Friern Barnet?
For Friern Barnet we work from the London rate: £2,340–£3,510 per square metre of new floor, including VAT, standard specification. London prices sit at the top of our range because of labour rates, access through the house, parking suspensions and skip licences.
| Size | Guide price inc VAT |
|---|---|
| 3 m × 5 m footprint, two floors (30 m²) | £70,000–£105,500 |
| 4 m × 6 m footprint, two floors (48 m²) | £112,500–£168,500 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a two-storey rear extension in Friern Barnet?
The planning route for a two-storey rear extension in Friern Barnet is set by England's householder rules and your council.
England's rules allow a rear extension of more than one storey without an application only when it is no deeper than 3 metres and at least 7 metres from the boundary opposite the rear wall, and never on designated land. Most two-storey schemes need householder planning permission.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Friern Barnet like to extend?
Period terraces in Friern Barnet sit alongside flats, and the difference matters: houses usually keep permitted development rights, while flats and maisonettes need planning permission for any rear extension.
How a two-storey rear extension in Friern Barnet comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Two-storey rear extensions near Friern Barnet
We also build two-storey rear extensions in nearby Muswell Hill (1.7 miles) and Finchley (1.8 miles).
- Two-storey rear extension in Muswell Hill
- Two-storey rear extension in Finchley
- Two-storey rear extension in Wood Green
- Two-storey rear extension in Palmers Green
- Two-storey rear extension in Totteridge
Other work in Friern Barnet:
FAQ
Two-storey rear extension questions in Friern Barnet
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
How long does a rear extension take to build in Friern Barnet?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Does a two-storey rear extension need planning permission?
Almost always. England and Northern Ireland allow 3 metres without an application only if at least 7 metres remains to the rear boundary; Wales and Scotland are similar or stricter.
What postcode areas do you cover around Friern Barnet?
Including N11, N12 and N20, and the surrounding Greater London area.
Do I need planning permission for a rear extension in Friern Barnet?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.
Is the site visit in Friern Barnet free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.