Extensions over a garage for homes in Harlesden
A over-garage extension in Harlesden starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in HarlesdenFrom £31,000 inc VAT
- PlanningHouseholder application needed
- Build time12–18 weeks on site
- Postcode districtsNW10
Extensions in and around Harlesden
Postcode districts we cover around Harlesden include NW10. We also work in nearby Willesden (1 mile), Cricklewood (2 miles), Wembley (2 miles), Acton (2 miles).
Just over the Hertfordshire border, Borehamwood is about 8 miles away. In London, space is at a premium and gardens are often short, so side returns, wraparounds and carefully planned rear extensions tend to make the most of every metre.
Will the council need to approve it?
In England any side extension over one storey, including a room built over a side garage, needs a householder planning application. The fee is £548 from 1 April 2026 and councils aim to decide within 8 weeks.
The planning position for a specific Harlesden address depends on its history and any designations, which is why we check it at the first visit.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
When an over-garage extension makes sense
- Families needing a bedroom without losing garden
- Detached and link-detached houses with an attached garage
- Homes where the landing can connect to the new room
Fitting the new room to the existing landing is the planning puzzle inside the house. We design the connection first, then the roof, so the extension does not end up with awkward steps or a corridor through a bedroom.
Over-garage extension prices in Harlesden
Prices below are for Harlesden, using the London factor of ×1.3. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Harlesden: £2,340 to £4,420 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Over a single garage 12 m² | £31,000 – £38,500 | £32,500 – £42,500 | £42,000 – £53,500 |
| Over a large single garage 16 m² | £37,000 – £46,000 | £43,500 – £56,500 | £56,000 – £71,000 |
| Over a double garage 24 m² | £56,000 – £69,000 | £65,500 – £84,500 | £84,000 – £106,500 |
For a figure based on your own dimensions, use our guide-price tool.
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Over-garage extension questions answered
Do I need building regulations approval in Harlesden?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Harlesden, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of Harlesden?
Yes. We cover Harlesden and the surrounding parts of Greater London. Site visits are free and there is no obligation.
Can I keep using the garage during the build?
Usually not for parking. The garage roof is removed and the space below is used for access and props for part of the build.
How much does a room over a garage cost?
Our guide range is about £2,340 to £4,420 per m² including VAT. A single-garage room of about 12 m² usually costs £32,500 to £42,500 at standard spec, more if the garage needs rebuilding.
Book a free site visit in Harlesden
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.