Barnet, Greater London
Rear extension planning drawings in Barnet
Rear extension planning drawings in Barnet: measured survey, design options, planning drawings and the application, handled for you. We measure the house, show you what the rules allow, price it in writing and build it.
Barnet and its postcode districts EN4, EN5, N3 and N12 are part of our Greater London coverage. For Barnet homes we start with a measured survey, then draw options before anything is submitted.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
What do rear extension planning drawings cost in Barnet?
As a guide, £1,000–£2,500 including VAT for a single-storey rear extension, or £2,000–£3,500 for a two-storey scheme. A householder planning application in England costs £548 (£575 for applications made from 8 December 2026), and a lawful development certificate for proposed work costs half the householder fee. Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission for a rear extension in Barnet?
Whether your rear extension in Barnet needs a planning application depends on its size, your house and any local restrictions.
A two-storey rear extension can be permitted development in England only if it projects no more than 3 metres, stays at least 7 metres from the rear boundary, matches the existing roof pitch and has obscure-glazed upper side windows. In practice most double-storey rear extensions go through a householder planning application.
Councils aim to decide householder applications within 8 weeks of validation, and prior approval within 42 days.
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 Barnet like to extend?
Barnet is mostly 1930s semis, short terraces and post-war houses, so full-width single-storey and two-storey rear extensions are realistic on many plots. Some later estates had permitted development rights removed by condition, so we check the planning history first.
How a rear extension in 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.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
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.
Rear extension planning drawings near Barnet
Close by, we work in New Barnet, about 1.1 miles away, and Totteridge, about 1.2 miles away.
- Rear extension planning drawings in New Barnet
- Rear extension planning drawings in Totteridge
- Rear extension planning drawings in East Barnet
- Rear extension planning drawings in Hadley Wood
- Rear extension planning drawings in Cockfosters
Other work in Barnet:
FAQ
Rear extension planning drawings questions in 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.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
Do I need an architect?
You need accurate drawings by someone who knows householder planning; we provide them.
Is the site visit in Barnet free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
Do I need planning permission for a rear extension in 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.
What postcode areas do you cover around Barnet?
Including EN4, EN5, N3, N12, N20 and NW7, and the surrounding Greater London area.