How much does a garage conversion cost?
Converting a garage into a room is one of the most cost-effective ways to add space. Get an indicative all-in figure below.
What a garage conversion involves
- 1Block up and insulate
Block up the garage door, insulate the floor, walls and roof to habitable standards.
- 2Floor and services
Raise and insulate the floor, run electrics and heating, and add windows for light.
- 3Finish and Building Regs
Plaster, decorate and comply with Building Regs (fire, ventilation, insulation).
A garage conversion is often the cheapest pound-per-square-metre way to add a room — attractive for adding an HMO bedroom or a downstairs bedroom/office to lift value. Insulation and floor build-up are where the cost sits.
Garage conversion costs (indicative)
| Scope | Result | Indicative cost |
|---|---|---|
| Single garage → room | Habitable room | £6,000 – £12,000 |
| Single garage → en-suite room | Room + shower | £10,000 – £18,000 |
| Double garage | Larger room / two rooms | £12,000 – £22,000 |
| With kitchenette (annexe) | Self-contained | £15,000 – £28,000 |
Includes insulation, blocking the door, floor build-up, electrics and finish. Structural changes add cost.
Frequently asked questions
How much does a garage conversion cost?+
Converting a single integral garage into a habitable room typically costs £6,000–£12,000 all-in; adding an en-suite or kitchenette costs more. It's one of the cheapest ways to add floor area.
Do I need planning permission?+
Internal garage conversions are often permitted development, but Building Regs approval is required. Check for Article 4 or conditions removing PD rights in your area.
Related tools & guides
Want to know how these figures are calculated? See our cost methodology.
Cost figures shown are indicative estimates, not quotations. You are responsible for verifying all costs (obtain contractor quotes) and any figures submitted to a lender. ScopeWise is a documentation tool, not financial, tax, structural or planning advice. HMO compliance prompts are guidance only — confirm requirements with your local council, as standards and licensing vary by authority.