Belsize Park, Greater London
Rear extension planning drawings in Belsize Park
We plan and build rear extensions for homeowners in Belsize Park. Measured survey, design options, planning drawings and the application, handled for you. Start with a free site visit, then a written price once the design is agreed.
Belsize Park and its postcode districts NW3, NW6 and NW8 are part of our Greater London coverage. Planning applications in Belsize Park go to the local planning authority covering Belsize Park, and we check its local design guidance for rear extensions before drawing.
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 Belsize Park?
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 Belsize Park?
Whether your rear extension in Belsize Park 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 Belsize Park like to extend?
Period terraces in Belsize Park 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 rear extension in Belsize Park comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Rear extension planning drawings near Belsize Park
We also build rear extensions in nearby Kilburn (0.9 miles) and Chalk Farm (1.0 miles).
- Rear extension planning drawings in Kilburn
- Rear extension planning drawings in Chalk Farm
- Rear extension planning drawings in Camden Town
- Rear extension planning drawings in Highgate
- Rear extension planning drawings in Maida Hill
Other work in Belsize Park:
FAQ
Rear extension planning drawings questions in Belsize Park
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.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
What if planning is refused?
We review the reasons with you, amend and resubmit (often free of a second fee within 12 months in England) or appeal.
Is the site visit in Belsize Park free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
How long does a rear extension take to build in Belsize Park?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.