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Hanworth, Greater London

Semi-detached rear extension in Hanworth

We plan and build rear extensions for semi-detached houses for homeowners in Hanworth. Single or two-storey extensions for semi-detached houses, with side access and one party wall. Start with a free site visit, then a written price once the design is agreed.

Hanworth sits in Greater London, with postcode districts including TW2, TW12 and TW13. Where a Hanworth semi already has a small lean-to at the back, we usually replace it rather than extend it.

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 semi-detached rear extension cost in Hanworth?

A semi-detached rear extension in Hanworth is priced at £2,470–£4,030 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.

Semi-detached rear extension prices in Hanworth
SizeGuide price inc VAT
3 m wide × 4 m deep (12 m²)£29,500–£48,500
4 m wide × 5 m deep (20 m²)£49,500–£80,500
4 m wide × 6 m deep (24 m²)£59,500–£96,500

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 semi-detached rear extension in Hanworth?

Here is how the rules in England apply to a semi-detached rear extension in Hanworth.

English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.

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.

If 3 or 4 metres is not enough, England's prior approval route allows 6 metres on a terraced or semi-detached house and 8 metres on a detached house for a single-storey rear extension. Neighbours are consulted, the council decides within 42 days, and the fee is £249, rising to £310 from 8 December 2026.

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 Hanworth like to extend?

Much of Hanworth 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 semi-detached rear extension in Hanworth comes together

  1. 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.

  2. Options and costs

    We draw layout options and price each one, so the budget shapes the design rather than surprising you later.

  3. Paperwork handled

    Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.

  4. 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.

Semi-detached rear extensions near Hanworth

From Hanworth, the nearest places we also cover are Hampton (1.5 miles) and Feltham (1.6 miles).

Other work in Hanworth:

All rear extensions in Hanworth

FAQ

Semi-detached rear extension questions in Hanworth

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.

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

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 match pebbledash or render?

Yes. Many semis are refinished with new render across the whole back elevation so old and new match.

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.

Is the site visit in Hanworth 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.

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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