Garage conversion cost
Integral and detached garage conversion costs for 2025. In the UK, expect to pay between £6,000 and £50,000, with the typical project around £12,000 (average integral garage conversion). Regional variation, specification tier and site access conditions all shift the final quote.
Homeowners researching this typically also price up garden room cost. For wider context, browse our bathroom pricing, kitchen pricing and boiler & heating costs.
Cost table
| Item | Typical range (GBP) |
|---|---|
Basic integral garage conversion — Insulation, plasterboard, floor, electrics only | £6,000–£12,000 |
Full integral conversion (room) — Full fit-out, toilet, high spec finish | £10,000–£20,000 |
Detached garage conversion — Requires new services, more complex | £15,000–£35,000 |
Double garage conversion — Two rooms or large open plan | £16,000–£40,000 |
Garage conversion to annexe — Self-contained unit with kitchen/bathroom | £20,000–£50,000 |
Labour costs
Labour typically accounts for 50% of the total project cost in the UK.
| Item | Typical range (GBP) |
|---|---|
Builder (structural work) | £3,000–£8,000 |
Electrician | £800–£2,500 |
Plumber (if bathroom added) | £1,500–£4,000 |
Plasterer | £600–£1,500 |
Decorator | £500–£1,200 |
Building regulations inspector | £150–£400 |
Materials costs
Materials and fittings make up the remainder of the budget, with specification tier driving most of the variation.
| Item | Typical range (GBP) |
|---|---|
Insulation (walls, floor, ceiling) | £800–£2,500 |
Plasterboard & skim | £600–£1,500 |
Concrete floor / screed | £500–£1,500 |
New door / window | £500–£2,000 |
Electrical fittings | £400–£1,200 |
Heating (radiator or UFH) | £500–£2,500 |
Factors affecting cost in the UK
- ·Region — London and the South East run 15–30% above national averages.
- ·Specification tier — premium materials and finishes can double the base cost.
- ·Access and site conditions — flats, restricted parking and listed buildings add time.
- ·Scope changes mid-project — late design decisions are the biggest cost overrun driver.
- ·Trade availability — quotes rise 10–20% in peak spring and summer months.
Ways to reduce cost
- ·Keep the existing roof if it's sound rather than re-pitching.
- ·Block up the garage door opening with masonry rather than a full window/wall feature.
- ·Extend existing heating from the adjacent room rather than adding a new boiler zone.
- ·Use a builder under a JCT minor works contract rather than a specialist garage conversion company.
- ·Combine the conversion with a planned re-decoration of adjoining rooms to share trades.
Frequently asked questions
- Do I need planning permission to convert a garage?
- Converting an integral (attached) garage is usually permitted development and does not require planning permission. However, if the garage is detached, listed, in a conservation area, or in a flat or maisonette, you will typically need full planning permission.
- How long does a garage conversion take?
- A basic integral garage conversion takes 3–6 weeks. A full fit-out with toilet and utility room takes 6–10 weeks. Detached garage conversions with new services may take 10–16 weeks.
- Does a garage conversion add value?
- Yes — converting a garage into a habitable room typically adds 10–20% to property value and costs less than a full extension. However, losing garage parking can be a negative in areas where off-street parking is scarce.
- Do I need building regulations approval?
- Yes, always — garage conversions are notifiable works under building regulations. You'll need to ensure insulation, structural, fire safety, ventilation, and electrical standards are met. Your local authority building control or a private approved inspector can oversee this.
- Can a converted garage be used as a bedroom?
- Yes, subject to meeting building regulations for habitable rooms: minimum ceiling height of 2.1m, adequate natural light and ventilation, adequate insulation (thermal and acoustic), and appropriate fire safety.
Sources & how we estimate
Prices are typical UK ranges compiled by ModernExpert.AI from published trade rates and supplier price lists, and are estimates — always get at least three written quotes. Rules on permissions, safety and certification come from the official sources below. Last reviewed 19 October 2026.
- Planning Portal — Extensions
- GOV.UK — Party Wall etc. Act 1996 explained
- GOV.UK — Building regulations approval
- Planning Portal — Do you need permission?
- ONS — Construction output price indices
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