How much does a garage conversion cost in the UK?
A garage conversion is usually cheaper per square metre than an extension because the structure already exists — but floors, damp, insulation and heating still have to be brought up to habitable standard.
The main variables are the state of the existing floor and walls, how the old door opening is filled, and whether a bathroom or kitchen is being added.
Building regulations apply even where planning permission does not. Insulation, ventilation, fire safety and, where relevant, structural changes all need to comply.
Indicative UK cost ranges
QuoteCheck does not hold a live UK pricing feed. The figures below are indicative planning ranges, assembled from commonly published UK ranges and typical job structures, and they are deliberately wide. Treat them as a starting point for questions, not as a valuation. Real prices depend on specification, access, ground conditions, region, season and how each firm prices its own labour and overheads.
| Item | Unit | Indicative range |
|---|---|---|
| Standard single garage conversionHabitable room, no plumbing. | per project | £8,000 – £20,000 |
| Conversion including shower roomDrainage runs affect cost significantly. | per project | £14,000 – £28,000 |
| Filling the garage door openingIncludes new window or door. | per opening | £1,200 – £3,000 |
| New insulated floorDepends on existing slab and damp-proofing. | per m² | £90 – £180 |
| Electrics and heatingRadiator, circuits and certification. | per project | £1,500 – £4,000 |
| Building controlRequired for habitable conversion. | per job | £400 – £900 |
What moves the price
- Existing slab
- Whether it can be insulated over or must be dug out.
- Damp and ventilation
- Garages are rarely built to habitable standards.
- Drainage
- Adding a WC or shower may require a pump or new run.
- Heating capacity
- Whether the existing boiler can take another radiator.
- Structural changes
- New openings into the house need support.
- Parking
- Some areas require replacement off-street parking.
Worked example — single garage to home office (illustrative only)
- Fill opening, new window
- £2,200
- Insulated floor, 15m²
- £1,900
- Insulation, plasterboard and skim
- £3,200
- Electrics and heating
- £2,100
- Flooring and decoration
- £1,600
- Building control
- £650
- Indicative total before VAT
- £11,650
Fictional figures showing the typical structure of a conversion price.
What your quote should show
- How the existing floor is being treated
- Insulation specification for floor, walls and roof
- How the door opening is filled and what replaces it
- Heating and electrical work, with certification
- Damp-proofing and ventilation
- Building control application and fees
- Decoration and flooring inclusion
- VAT treatment and programme
Frequently asked questions
How much does a garage conversion cost in the UK?
Indicatively £8,000–£20,000 for a standard single garage converted to a habitable room, and more where plumbing or structural work is involved.
Do I need planning permission to convert a garage?
Often not, where the work is internal and the property is not subject to restrictions, but building regulations always apply. Check with your local authority.
Will converting my garage affect my home insurance?
It can. Tell your insurer about any change of use or structural alteration.
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