Friern Barnet, Greater London
Side return extension in Friern Barnet
For homes in Friern Barnet, a side return extension is often the simplest way to gain space without moving. Infilling the narrow passage beside a Victorian or Edwardian back addition. We take it from survey to completion certificate.
Friern Barnet sits in Greater London, with postcode districts including N11, N12 and N20. Side return projects in Friern Barnet usually start with a drainage survey of the side passage.
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 side return extension cost in Friern Barnet?
Guide prices for a side return extension in Friern Barnet start from our London rate of £2,990–£4,940 per square metre, including VAT. 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 |
|---|---|
| 2 m wide × 6 m deep (12 m²) | £36,000–£59,500 |
| 2.5 m wide × 7 m deep (17.5 m²) | £52,500–£86,500 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a side return extension in Friern Barnet?
Planning for a side return extension in Friern Barnet follows the English householder rules.
Side return infills and the side leg of a wraparound are treated as side extensions in England: single-storey, no more than 4 metres high and no wider than half the original house. They are not permitted development in conservation areas, National Parks or National Landscapes, and a joined wraparound often needs a planning application because the side and rear rules apply together.
The Party Wall etc. Act 1996 applies in England: you serve notice two months before work to a shared wall, and one month before digging foundations within 3 metres (or 6 metres for deeper foundations) of a neighbour's building. Neighbours can agree in writing; if they dissent, surveyors agree an award.
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 side return 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.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Side return extensions near Friern Barnet
Close by, we work in Muswell Hill, about 1.7 miles away, and Finchley, about 1.8 miles away.
- Side return extension in Muswell Hill
- Side return extension in Finchley
- Side return extension in Wood Green
- Side return extension in Palmers Green
- Side return extension in Totteridge
Other work in Friern Barnet:
FAQ
Side return extension questions in Friern Barnet
What postcode areas do you cover around Friern Barnet?
Including N11, N12 and N20, and the surrounding Greater London area.
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.
Can I combine a side return with a rear extension?
Yes; that is a wraparound extension, and it gives the biggest open-plan room a terrace can have.
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.
Do you handle building control in Friern Barnet?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
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.