A garage conversion turns an integral or attached garage into a warm, habitable room by insulating the floor, walls and ceiling, replacing the garage door with a wall and window, and adding heating, lighting and finishes.
Every house in Harrow is a little different, so we never price a garage conversion from a brochure. We look at the structure, access and existing finishes first, then put in writing a fixed figure for the scope we settle on. As a rough steer, homeowners in London should budget £15,500–£36,500 including VAT, with work typically taking 2–6 weeks on site.
- Guide price
- £15,500–£36,500 inc VAT
- Time on site
- 2–6 weeks on site
- Postcodes
- HA1, HA2, HA3, HA5 and HA7
- Planning rules
- England
- Local area
- Greater London
- Survey
- Free, with a written quote
How much does a garage conversion cost in Harrow?
What will a garage conversion cost in Harrow? Our guide range is £15,500–£36,500 including VAT. That figure is adjusted for London, about 30% above the national guide, and is intended for planning a budget. A firm written price for your chosen specification follows a free survey at your home.
| Type of job | What it usually involves | Guide in Harrow |
|---|---|---|
| Integral single garage | A garage within the house footprint, with sound walls and a roof already in place. | £13,000–£23,500 |
| Attached single garage | A garage beside the house that may need roof, wall or floor upgrades. | £18,000–£32,500 |
| Double or detached garage | A larger or separate building, often with a shower room or kitchenette. | £28,500–£58,000 |
Expect these to shape the final quote:
- Garage type: integral, attached or detached
- Condition of the floor, walls, roof and foundations
- Whether a shower room or kitchenette is included
- Heating method and ventilation for the new room
What’s included?
- Foundation checks under the door opening and footings where needed
- Damp-proof membrane, insulated floor and screed or raised timber floor
- Insulated walls and ceiling built to building regulations
- New internal door or opening into the house
- Plastering, skirting and decoration-ready finish
- Building control inspections and completion certificate
Local housing and a garage conversion
London's housing is dominated by Victorian and Edwardian terraces, often in yellow London stock brick, with Georgian terraces in central districts and mansion blocks across many inner areas. Outer boroughs have large belts of interwar semis, and there are extensive post-war council estates. Many houses have been split into flats, and conservation areas are widespread.
Terraces suit side-return extensions and rear dormer loft conversions; interwar semis commonly take hip-to-gable lofts. Shared party walls, restricted parking and conservation rules often shape the plans and the programme.
For a garage conversion in Harrow, this means checking things like wall construction, roof structure and existing services before we put a figure on paper.
Permissions for a garage conversion in Harrow
As Harrow is in England, read the following with that system of planning and building control in mind. We check what applies to your house with the council before you receive a quote.
In England, converting an attached or integral garage into a room usually needs no planning permission, unless a planning condition on your estate has removed permitted development rights (common on newer houses). Changing the garage door to a wall and window is generally fine.
Building Regulations approval is needed: foundations for the infill wall, a damp-proof course, insulation, ventilation and fire safety.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
How does the job run?
Survey and measure
We begin by looking at the job in person. During the free survey we discuss options, materials and budget for a garage conversion, and photograph or measure anything the quote needs to reflect.
Written quote
We put everything into a written, fixed-price quote: the specification, what's excluded, staged payments and the expected time on site. Take whatever time you need to decide; there's no pressure to commit.
Booking the work
With the quote agreed, we book the work in and handle preparation: permissions where needed, building control notifications, material orders and access arrangements for your Harrow property.
Finish and handover
The work is carried out to the agreed specification, with floors and furniture protected and the site kept tidy. At the end we clean up, walk through the finished job with you and hand over any certificates.
Why homeowners choose us
Questions about a garage conversion in Harrow
Will losing the garage affect parking?
Losing a garage can matter if your street has parking pressure or your property deeds or planning conditions require off-street parking. Many garages are too narrow for modern cars, so in practice the driveway often provides the parking anyway. We check for planning conditions affecting the garage before quoting. If you need extra parking, we can also price a driveway extension.
Which postcodes in Harrow do you cover?
We cover HA1, HA2, HA3 and HA5, along with the rest of London. If your postcode is not listed, get in touch anyway: our coverage is UK-wide, and we can usually arrange a survey wherever you live. Enter your postcode in the guide-price tool or contact form and we will confirm.
How long does a garage conversion take?
A straightforward integral garage conversion usually takes two to four weeks on site. Attached garages that need roof or wall upgrades, and conversions with a shower room, typically take four to six weeks. Detached garages turned into annexes can take longer. Before work starts, allow time for drawings and building control approval. We give you a clear programme with your written quote.
Who do I deal with during the job?
One point of contact manages your project from survey to handover. They schedule the trades working under our contract, keep you updated on progress, and are the person to call with any question. You don't need to coordinate builders, electricians or decorators separately, because that is part of what we do.
Do I need planning permission for a garage conversion?
Whether a garage conversion needs planning permission depends on the works, your home's location, whether it is listed or in a conservation area, and which UK nation you are in. In England, converting an integral or attached garage is often permitted development where changes are mostly internal, unless a planning condition has removed those rights, which is common on newer estates. We check what applies before quoting.
Also covering areas around Harrow
If your address falls within HA1, HA2, HA3 and HA5, we cover it. The same goes for neighbouring Wealdstone, Brent and Wembley, which we include alongside Harrow when arranging surveys and quotes.