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Greater London

Glazed and glass-box rear extensions in Greater London

Full-height glass, slim frames and big rooflights for the most open rear room. Rear extensions in Greater London: we cover 187 towns including Islington, Bexley and Barking, with design, approvals and the build under one contract.

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Highly glazed rear extension with full-height sliding glass doors, a glass box corner and a walk-on rooflight

A wide sliding door with one long rooflight, rather than a fully glazed roof, keeps a glass-led extension usable in summer. 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 glazed rear extension cost in Greater London?

In Greater London, our guide for a glazed rear extension is £3,640–£6,240 per square metre including VAT for a standard specification. London prices sit at the top of our range because of labour rates, access through the house, parking suspensions and skip licences.

Glazed rear extension guide prices in Greater London
SizeGuide price inc VAT
3 m wide × 4 m deep (12 m²)£43,500–£75,000
4 m wide × 6 m deep (24 m²)£87,500–£150,000

These are guide ranges; the written quote after the survey is the figure that counts.

Do you need planning permission in Greater London?

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.

New fabric must meet Approved Document L (2021 edition incorporating 2023 amendments): walls 0.18, roof 0.15 and floor 0.18 W/m²K, windows 1.4 W/m²K or Band B. Under the simple route, new windows, doors and rooflights should not exceed 25% of the extension floor area plus any openings removed; more glass is possible with a whole-house calculation.

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?

FAQ

Questions people ask

Will a glass extension be too hot?

Not if it is designed for its orientation, with solar-control glass, shading and ventilation.

Is there a limit on how much glass I can have?

In England the simple rule is 25% of the floor area plus openings removed; more is allowed with a calculation showing the house still meets Part L.

Sliding or bifold doors?

Sliders give bigger panes and slimmer sightlines; bifolds open the whole width. Our guide compares them.

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.

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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