Glazed rear extension in Harrow

How much does a glazed rear extension cost in Harrow?

In Harrow, 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.

Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.

Do you need planning permission for a glazed rear extension in Harrow?

Planning for a glazed rear extension in Harrow follows the English householder rules.

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.

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. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.

What are homes in Harrow like to extend?

Much of Harrow 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 glazed rear extension in Harrow 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. Drawings and budget

   Floor plans and elevations for the options, each with a guide price.

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.

Glazed rear extensions near Harrow

We also build glazed and glass-box rear extensions in nearby Harrow on the Hill (0.5 miles) and Headstone (1.1 miles).

• Glazed rear extension in Harrow on the Hill
• Glazed rear extension in Headstone
• Glazed rear extension in Wealdstone
• Glazed rear extension in Sudbury
• Glazed rear extension in Harrow Weald

Other work in Harrow:

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

All rear extensions in Harrow