Blackheath, Greater London
Two-storey rear extension in Blackheath
For homes in Blackheath, 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.
Blackheath sits in Greater London, with postcode districts including SE3, SE10 and SE13. 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 Blackheath?
A two-storey rear extension in Blackheath is priced at £2,340–£3,510 per square metre including VAT as a guide, before kitchen fit-out and fees. 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 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a two-storey rear extension in Blackheath?
Planning for a two-storey rear extension in Blackheath follows the English householder rules.
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.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. Before any drawing we look up the property's history with the council, because earlier extensions and removed rights change the answer.
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 two-storey rear extension in Blackheath 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.
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.
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.
Two-storey rear extensions near Blackheath
Neighbouring places we cover include Lee (0.6 miles) and Kidbrooke (0.8 miles).
- Two-storey rear extension in Lee
- Two-storey rear extension in Kidbrooke
- Two-storey rear extension in Greenwich
- Two-storey rear extension in Ladywell
- Two-storey rear extension in Catford
Other work in Blackheath:
FAQ
Two-storey rear extension questions in Blackheath
Can you match the brick or stone on my Blackheath house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
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.
Is two-storey cheaper per square metre than single-storey?
Usually yes, because the foundations and roof are shared across twice the floor area. The total cost is higher.
How long does a rear extension take to build in Blackheath?
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 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 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.