Greater London

Rear extensions for detached houses in Greater London

Wider, deeper rear extensions with room for vaulted roofs and big glazing. We design and build rear extensions across Greater London, from Islington and Bexley to Barking, covering single-storey kitchen extensions, two-storey additions, side returns and wraparounds.

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Wide single-storey rear extension with an oak-framed glazed gable on a detached brick house

Detached houses in Greater London often have room for a deeper rear extension under England's prior approval route or a full-width design. Much of Greater London 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 much does a detached house rear extension cost in Greater London?

A detached house rear extension in Greater London is priced at £2,540–£4,160 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.

Detached house rear extension guide prices in Greater London
Size	Guide price inc VAT
4 m wide × 6 m deep (24 m²)	£61,000–£100,000
5 m wide × 8 m deep (40 m²)	£101,500–£166,500

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 in Greater London?

In England a single-storey rear extension can often be built under permitted development: up to 3 metres beyond the original rear wall of an attached house, or 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres if any part is within 2 metres of a boundary.

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.

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.

Where in Greater London do we work?

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FAQ

Questions people ask

How deep can I extend a detached house?

4 metres under permitted development in England, or 8 metres with prior approval, outside designated land.

Can I have a vaulted ceiling?

Yes, with a pitched roof and exposed or boxed rafters, subject to the height limits.

Is an oak frame worth it?

It is a premium finish with a long life; it costs more than blockwork with a plain roof.

Do you cover all of Greater London?

We cover 187 towns and districts in Greater London, including Islington, Bexley and Barking.

Who builds the extension?

Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.