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Streatham, Greater London

Rear extension planning drawings in Streatham

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

Streatham is covered from our Greater London round, including SE27, SW12 and SW16. 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 Streatham?

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 Streatham?

Planning for a rear extension in Streatham 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.

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 Streatham like to extend?

Period terraces in Streatham 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 Streatham comes together

  1. Survey visit

    We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.

  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 Streatham

We also build rear extensions in nearby Furzedown (0.7 miles) and Norbury (1.1 miles).

Other work in Streatham:

All rear extensions in Streatham

FAQ

Rear extension planning drawings questions in Streatham

Do I need planning permission for a rear extension in Streatham?

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.

Is the site visit in Streatham free?

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

Can I see the design in 3D?

Yes; we produce simple 3D views so you can judge the size and light.

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

Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.

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.

What postcode areas do you cover around Streatham?

Including SE27, SW12 and SW16, 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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