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Carshalton, Greater London

Rear extension planning drawings in Carshalton

Measured survey, design options, planning drawings and the application, handled for you. If you live in Carshalton 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.

We cover Carshalton (SM1, SM5 and SM6) as part of our Greater London work. Rear extension applications in Greater London are householder applications, which councils aim to decide within about eight weeks.

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 Carshalton?

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 Carshalton?

Whether your 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.

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. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.

What are homes in Carshalton like to extend?

Much of Carshalton is 1920s and 1930s semis and short terraces with longer gardens than inner London, which suit full-width single-storey rear extensions. Parking suspensions, skip licences and controlled hours on residential streets shape the programme more than the build itself.

How a rear extension in Carshalton comes together

  1. 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.

  2. Drawings and budget

    Floor plans and elevations for the options, each with a guide price.

  3. Approvals

    Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.

  4. 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 Carshalton

From Carshalton, the nearest places we also cover are Wallington (0.7 miles) and St Helier (1.2 miles).

Other work in Carshalton:

All rear extensions in Carshalton

FAQ

Rear extension planning drawings questions in Carshalton

Is the site visit in Carshalton free?

Yes. We visit, measure up and talk through the options with no cost and no obligation.

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 planning conditions affect the build?

Yes, for example matching materials or obscure glazing. We plan for them.

How long does a rear extension take to build in Carshalton?

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 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.

What postcode areas do you cover around Carshalton?

Including SM1, SM5 and SM6, and the surrounding Greater London area.

Next step

See what your rear extension would cost

Get a guide price online in a couple of minutes, or book a free site visit and we'll measure up and talk you through the planning route.

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