Forest Hill, Greater London
Two-storey rear extension in Forest Hill
Two-storey rear extension in Forest Hill: a larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. We measure the house, show you what the rules allow, price it in writing and build it.
Forest Hill is covered from our Greater London round, including SE4, SE6 and SE23. Two-storey rear extensions suit semi-detached houses in Forest Hill best, where the extra bedroom matters as much as the bigger kitchen.
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 Forest Hill?
Guide prices for a two-storey rear extension in Forest Hill start from our London rate of £2,340–£3,510 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 |
|---|---|
| 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 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a two-storey rear extension in Forest Hill?
Planning for a two-storey rear extension in Forest Hill 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. 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 Forest Hill like to extend?
Period terraces in Forest Hill 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 Forest Hill 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.
Two-storey rear extensions near Forest Hill
We also build two-storey rear extensions in nearby Crofton Park (0.5 miles) and Perry Vale (0.7 miles).
- Two-storey rear extension in Crofton Park
- Two-storey rear extension in Perry Vale
- Two-storey rear extension in Catford
- Two-storey rear extension in Ladywell
- Two-storey rear extension in Brockley
Other work in Forest Hill:
FAQ
Two-storey rear extension questions in Forest Hill
Is the site visit in Forest Hill free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
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.
Does a two-storey rear extension need planning permission?
Almost always. England and Northern Ireland allow 3 metres without an application only if at least 7 metres remains to the rear boundary; Wales and Scotland are similar or stricter.
Can you match the brick or stone on my Forest Hill house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
How much does a two-storey rear extension cost in Forest Hill?
As a guide, £2,340–£3,510 per square metre including VAT for a standard specification. For example, 3 m × 5 m footprint, two floors (30 m²): about £70,000–£105,500 at that rate. Your written price follows the survey.
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.