Semi-detached rear extension in Bexley

How much does a semi-detached rear extension cost in Bexley?

For Bexley we work from the London rate: £2,470–£4,030 per square metre of new floor, including VAT, standard specification. London prices sit at the top of our range because of labour rates, access through the house, parking suspensions and skip licences.

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 semi-detached rear extension in Bexley?

The planning route for a semi-detached rear extension in Bexley is set by England's householder rules and your council.

Under England's householder permitted development rules you can usually add 3 metres at the back of an attached house, or 4 metres on a detached house, without a planning application, as long as the extension stays under 4 metres high and its eaves stay under 3 metres where it is within 2 metres of a boundary.

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.

England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.

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 Bexley like to extend?

Much of Bexley 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 Bexley 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. Design and guide price

   Two or three layout options with a guide price for each, so you choose the design knowing what it costs.

3. Planning and regulations

   We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.

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 Bexley

From Bexley, the nearest places we also cover are Sidcup (2.2 miles) and Welling (2.3 miles).

• Semi-detached rear extension in Sidcup
• Semi-detached rear extension in Welling
• Semi-detached rear extension in Dartford
• Semi-detached rear extension in Swanley
• Semi-detached rear extension in Belvedere

Other work in Bexley:

• Single-storey rear extension
• Two-storey rear extension
• Kitchen-diner rear extension
• Side return extension
• Wraparound extension
• Glazed rear extension

All rear extensions in Bexley