Blackheath, Greater London
Rear extension planning drawings in Blackheath
Measured survey, design options, planning drawings and the application, handled for you. If you live in Blackheath and want to know what a rear extension would cost and whether it needs planning, start with the online guide price or a free site visit.
Blackheath is covered from our Greater London round, including SE3, SE10 and SE13. For Blackheath 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 Blackheath?
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 Blackheath?
The planning route for a rear extension in Blackheath 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.
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 Blackheath like to extend?
Period terraces in Blackheath 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 Blackheath 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.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
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 Blackheath
We also build rear extensions in nearby Lee (0.6 miles) and Kidbrooke (0.8 miles).
- Rear extension planning drawings in Lee
- Rear extension planning drawings in Kidbrooke
- Rear extension planning drawings in Greenwich
- Rear extension planning drawings in Ladywell
- Rear extension planning drawings in Catford
Other work in Blackheath:
FAQ
Rear extension planning drawings questions in Blackheath
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.
Do I need planning permission for a rear extension in Blackheath?
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.
Can I see the design in 3D?
Yes; we produce simple 3D views so you can judge the size and light.
What postcode areas do you cover around Blackheath?
Including SE3, SE10 and SE13, and the surrounding Greater London area.
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.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.