Garage Conversion Cost UK 2026 · Single, Double & Detached
Real 2026 prices for converting a garage in the UK. Single garage from £8,000, double from £15,000, detached from £18,000. £900–£1,800/m² typical — the cheapest way to add habitable space without extending. Free quotes from local specialists.
Garage Conversion Cost at a Glance
Real cost ranges drawn from BestBuilders data across 519 UK towns. Use these as your starting benchmark — then get 3 local quotes for your exact garage.
12–18 m² habitable room. Typically a bedroom, office or playroom. 6–8 weeks on site. Most fall under permitted development.
Get quotes →25–35 m². Open-plan living space, en-suite annexe or large family room. Comfortably fits a kitchenette + bathroom.
Get quotes →Annexe, home office, gym or studio. Often needs planning permission. May require utilities trenching from main house.
Get quotes →Cost Per m² (UK 2026)
| Specification | Cost per m² | What's included |
|---|---|---|
| Basic — habitable room | £900 – £1,200 | Insulation, plasterboard, electrics, basic flooring, decoration |
| Mid — bedroom + en-suite | £1,200 – £1,500 | Above + plumbing, en-suite shower room, better finishes |
| High — annexe / studio | £1,500 – £1,800+ | Full self-contained annexe, kitchenette, premium finishes |
Cost per m² is significantly cheaper than a new-build extension (£2,000–£3,000/m²) because the shell, foundations and roof already exist.
Garage Conversion Cost by Region
| Region | Single garage | Double garage | Detached |
|---|---|---|---|
| London | £10,800 – £24,300 | £20,250 – £40,500 | £24,300 – £47,250 |
| South East | £10,000 – £22,500 | £18,750 – £37,500 | £22,500 – £43,750 |
| Midlands & SW | £7,600 – £17,100 | £14,250 – £28,500 | £17,100 – £33,250 |
| North & Yorkshire | £7,000 – £16,600 | £13,800 – £27,600 | £16,600 – £32,200 |
| Scotland, Wales & NI | £6,800 – £15,300 | £12,750 – £25,500 | £15,300 – £29,750 |
Garage Conversion Hidden Costs
Most builder quotes price the conversion only — there's a layer of project costs that catches first-time converters out.
�� Building regulations fees
Required for all garage conversions even when planning isn't. Building control submission and inspections.
📐 Architect / drawings
Most garage conversions need at least scale drawings for building control. A technician (not full architect) is usually adequate.
🔧 Damp-proofing & insulation upgrade
Older garages often have inadequate floor slabs (no DPM) and walls below current insulation standards. Both must be upgraded for habitable use.
🛁 Plumbing & drainage
Adding an en-suite or kitchenette requires running soil pipe to nearest drain — sometimes outside the existing fall line, needing a pump.
⚡ Electrical upgrade
A garage typically has 1–2 sockets — a habitable room needs 6–8 plus lighting circuit, possibly consumer-unit upgrade.
📊 Contingency (always include)
Surprises happen — buried obstacles, hidden damp, inadequate foundations. Industry standard 10–15% of total budget.
Get Accurate Quotes for Your Garage Conversion
Online guides give you a benchmark — accurate pricing requires a builder who has seen your garage. BestBuilders matches you with up to 3 vetted local specialists for free.