Semi-detached rear extension in Heston

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

In Heston, our guide for a semi-detached rear extension is £2,470–£4,030 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.

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

Do you need planning permission for a semi-detached rear extension in Heston?

Whether your semi-detached rear extension in Heston needs a planning application depends on its size, your house and any local restrictions.

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.

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. 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 Heston like to extend?

Heston is mostly 1930s semis, short terraces and post-war houses, so full-width single-storey and two-storey rear extensions are realistic on many plots. Some later estates had permitted development rights removed by condition, so we check the planning history first.

How a semi-detached rear extension in Heston 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. 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.

Semi-detached rear extensions near Heston

Close by, we work in Osterley, about 1.0 miles away, and Hounslow, about 1.2 miles away.

• Semi-detached rear extension in Osterley
• Semi-detached rear extension in Hounslow
• Semi-detached rear extension in Isleworth
• Semi-detached rear extension in Cranford
• Semi-detached rear extension in Southall

Other work in Heston:

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

All rear extensions in Heston