Harrow on the Hill, Greater London
Kitchen-diner rear extension in Harrow on the Hill
An open-plan kitchen, dining and family room that opens straight onto the garden. If you live in Harrow on the Hill and want to know what a kitchen-diner rear extension would cost and whether it needs planning, start with the online guide price or a free site visit.
Harrow on the Hill and its postcode districts HA1, HA2 and HA3 are part of our Greater London coverage. For Harrow on the Hill kitchens we plan the extraction route and the island drainage before the slab is poured, so nothing has to be chased in later.
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 kitchen-diner rear extension cost in Harrow on the Hill?
Guide prices for a kitchen-diner rear extension in Harrow on the Hill start from our London rate of £2,470–£4,030 per square metre, including VAT. 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 |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £29,500–£48,500 |
| 4 m wide × 5 m deep (20 m²) | £49,500–£80,500 |
| 4 m wide × 6 m deep (24 m²) | £59,500–£96,500 |
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 kitchen-diner rear extension in Harrow on the Hill?
Here is how the rules in England apply to a kitchen-diner rear extension in Harrow on the Hill.
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.
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 Harrow on the Hill like to extend?
Harrow on the Hill 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 kitchen-diner rear extension in Harrow on the Hill comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Kitchen-diner rear extensions near Harrow on the Hill
We also build kitchen-diner rear extensions in nearby Harrow (0.5 miles) and Sudbury (1.2 miles).
- Kitchen-diner rear extension in Harrow
- Kitchen-diner rear extension in Sudbury
- Kitchen-diner rear extension in Headstone
- Kitchen-diner rear extension in Wealdstone
- Kitchen-diner rear extension in Wembley
Other work in Harrow on the Hill:
FAQ
Kitchen-diner rear extension questions in Harrow on the Hill
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
Can I add a utility room?
Often. A narrow utility or boot room along one side keeps the washing machine out of the open-plan space.
How much does a kitchen-diner rear extension cost in Harrow on the Hill?
As a guide, £2,470–£4,030 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £29,500–£48,500 at that rate. Your written price follows the survey.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
Do you handle building control in Harrow on the Hill?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.