Carshalton, Greater London
Two-storey rear extension in Carshalton
We plan and build two-storey rear extensions for homeowners in Carshalton. A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. Start with a free site visit, then a written price once the design is agreed.
Carshalton sits in Greater London, with postcode districts including SM1, SM5 and SM6. 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 Carshalton?
Guide prices for a two-storey rear extension in Carshalton 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 Carshalton?
Whether your two-storey rear extension in Carshalton needs a planning application depends on its size, your house and any local restrictions.
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.
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 Carshalton like to extend?
Carshalton 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 two-storey rear extension in Carshalton 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.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
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 Carshalton
From Carshalton, the nearest places we also cover are Wallington (0.7 miles) and St Helier (1.2 miles).
- Two-storey rear extension in Wallington
- Two-storey rear extension in St Helier
- Two-storey rear extension in Sutton
- Two-storey rear extension in Belmont
- Two-storey rear extension in Cheam
Other work in Carshalton:
FAQ
Two-storey rear extension questions in Carshalton
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.
How much does a two-storey rear extension cost in Carshalton?
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.
Can I add an en-suite upstairs?
Yes. We plan the soil pipe route early so the bathroom sits where drainage works without boxing through the room below.
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.
Do I need planning permission for a rear extension in Carshalton?
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 you match the brick or stone on my Carshalton house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.