What is a garage conversion?

A garage conversion turns an integral or attached garage into habitable space, such as a study, playroom, bedroom or utility. The garage door is replaced with a wall and window, the floor is raised and insulated, and the walls and roof are brought up to building regulations.
How much does a garage conversion cost in Barnet?
In Barnet, a garage conversion typically costs £23,500–£39,000 for a single integral garage, including VAT at 20% (standard rate). Building costs in London run about 30% above the UK average, and the figures for Barnet are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A single integral garage | £23,500–£39,000 |
| Higher specification | £39,000–£49,000 |
The main things that change the cost:
- Heating and flooring
- Whether planning permission is needed
- Integral, attached or detached
- Bathroom or kitchen
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a garage conversion in Barnet?
Before anything is built in Barnet, we confirm which approvals apply in England. In England converting an integral or attached garage usually does not need planning permission, unless a condition on the house removed permitted development rights (common on estates built in recent decades) or the house is listed. Building regulations approval is always needed.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
We check this for your address before design work starts, so there are no surprises later.
What we handle
On a typical garage conversion we handle:
- Foundation check under the garage door opening
- Building control completion
- Electrics, heating and plastering
- Floor raised with insulation and damp-proof membrane
- New wall and window to replace the garage door
- Drawings and building control application
How long does it take?
The build itself usually takes 3 to 6 weeks on site. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in Barnet
Victorian and Edwardian terraces dominate many London streets, which is why side return, wraparound and mansard projects are so common here.
From EN5 outwards, we take on projects throughout Barnet and the surrounding parts of Greater London.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about garage conversions in Barnet
How long does a garage conversion take in Barnet?
Typically 3 to 6 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
Can a detached garage be converted?
Yes, but using it as separate living accommodation may need planning permission.
Can the floor be level with the house?
Yes. The garage floor is raised and insulated to match the house floor level.
How much does a garage conversion cost in Barnet?
In Barnet, a garage conversion typically costs £23,500–£39,000 for a single integral garage, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Do I need building regulations approval?
Yes. Converting a garage to a habitable room needs building control approval for insulation, ventilation, fire safety and the new wall.
