Harrow, Greater London
Side return extension in Harrow
Infilling the narrow passage beside a Victorian or Edwardian back addition. We design, get the approvals for and build side return extensions in Harrow and the surrounding area, with one contract from the first survey to building control sign-off.
Harrow and its postcode districts HA1, HA2, HA3 and HA5 are part of our Greater London coverage. Side returns suit the Victorian and Edwardian terraces found across parts of Greater London, where the kitchen sits in a narrow back addition.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a side return extension cost in Harrow?
For Harrow we work from the London rate: £2,990–£4,940 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.
| Size | Guide price inc VAT |
|---|---|
| 2 m wide × 6 m deep (12 m²) | £36,000–£59,500 |
| 2.5 m wide × 7 m deep (17.5 m²) | £52,500–£86,500 |
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 side return extension in Harrow?
Whether your side return extension in Harrow needs a planning application depends on its size, your house and any local restrictions.
Side return infills and the side leg of a wraparound are treated as side extensions in England: single-storey, no more than 4 metres high and no wider than half the original house. They are not permitted development in conservation areas, National Parks or National Landscapes, and a joined wraparound often needs a planning application because the side and rear rules apply together.
The Party Wall etc. Act 1996 applies in England: you serve notice two months before work to a shared wall, and one month before digging foundations within 3 metres (or 6 metres for deeper foundations) of a neighbour's building. Neighbours can agree in writing; if they dissent, surveyors agree an award.
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 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 side return extension in Harrow comes together
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.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
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.
Side return extensions near Harrow
Close by, we work in Harrow on the Hill, about 0.5 miles away, and Headstone, about 1.1 miles away.
- Side return extension in Harrow on the Hill
- Side return extension in Headstone
- Side return extension in Wealdstone
- Side return extension in Sudbury
- Side return extension in Harrow Weald
Other work in Harrow:
FAQ
Side return extension questions in Harrow
How much does a side return extension cost in Harrow?
As a guide, £2,990–£4,940 per square metre including VAT for a standard specification. For example, 2 m wide × 6 m deep (12 m²): about £36,000–£59,500 at that rate. Your written price follows the survey.
Is the site visit in Harrow free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
Is a side return permitted development?
Sometimes, as a side extension within the width and height limits, but not in conservation areas, and many terraces are in one.
How long does a rear extension take to build in Harrow?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
What postcode areas do you cover around Harrow?
Including HA1, HA2, HA3, HA5 and HA7, and the surrounding Greater London area.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.