How Much Does a Garage Conversion Cost Per m² in 2026? (UK)
A UK garage conversion in 2026 costs roughly £700–£2,000 per m² all-in, with most standard habitable conversions landing at £1,000–£1,400/m². For a typical single garage that is a total of £9,000–£18,000. The per-m² rate is driven by three things — spec (basic room vs en-suite), plumbing, and how much structural fixing the floor, damp and insulation need. This guide breaks down the cost per square metre by conversion type, size, and region, with a worked example and the hidden extras that catch homeowners out.
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How much is a garage conversion per m² in 2026?
Typical 2026 UK garage conversion rates by spec:
- Basic room (storage, utility, playroom) — £700–£1,000/m²
- Standard habitable room (bedroom, office) — £1,000–£1,400/m²
- Room + en-suite or kitchenette — £1,400–£2,000/m²
- Self-contained annex (full kitchen + bathroom) — £1,800–£2,500/m²
A single integral garage (13–15m²) typically totals £9,000–£18,000. Add 15–40% for London and the South East.
Garage Conversion Cost Per m² by Spec
The end use you choose sets the per-square-metre rate — plumbing and high-end finishes are what move you up the ladder.
Basic room — storage, utility, playroom
Insulation, damp-proofing, a levelled floor, plastered walls, basic electrics and a couple of radiators. No plumbing. The cheapest way to claim back the space as warm, dry, usable rooms.
Standard habitable room — bedroom or office
Everything in the basic spec plus full Building-Regs insulation, the garage door infilled with a new insulated wall and window, decent flooring, joinery and heating tied into the main system. The most common conversion we see.
Room + en-suite or kitchenette
Adds plumbing — a new soil/waste run, hot and cold feeds, and either a compact shower room or a kitchenette. Plumbing distance from the existing stack is the single biggest variable here.
Self-contained annex — full kitchen + bathroom
A fully independent living unit with its own kitchen, bathroom, heating and often a separate entrance. Highest per-m² rate because you are effectively fitting out a small home. May need planning permission if used as a separate dwelling.
What Moves Your Per-m² Rate
Two identical-size garages can land £5,000 apart. Here is what explains the spread.
1. Damp & floor build-up
Garage slabs sit lower than house floors and often lack a damp-proof membrane. Raising and tanking the floor adds £1,500–£4,000 depending on levels.
2. Infilling the garage door
Replacing the up-and-over door with an insulated cavity wall, window and matching brick or render costs £1,800–£3,500.
3. Insulation to Building Regs
Walls, floor and roof must hit current U-values. Insulating a single-skin garage properly adds £1,200–£3,000.
4. Plumbing distance
An en-suite or kitchenette far from the existing soil stack means long pipe runs or a macerator — add £1,500–£4,000.
5. Heating extension
Extending the central heating circuit or adding electric underfloor heating runs £700–£2,500 depending on boiler capacity.
6. Region
London labour is 25–40% above the national average and the South East 15–25%. The North and Midlands sit near or below average. See our builder directory.
Garage Conversion Cost Per m² by UK Region
Based on project data across 519 UK towns — standard habitable conversion of a single integral garage.
Rates are all-in per m² for a standard habitable conversion including infill, insulation, electrics, heating and finishes. Adding plumbing moves you into the next band.
Worked example (illustrative): Single Garage to Bedroom in Leicester
Integral single garage, 14m², converted to a double bedroom with built-in wardrobes. Completed March 2026, East Midlands.
| Building Regs application & inspections | £950 |
| Floor: damp membrane, insulation, screed | £2,600 |
| Garage door infill (wall, window, brick) | £2,800 |
| Wall & roof insulation + plasterboard | £2,900 |
| Electrics (lighting, sockets, consumer unit) | £1,650 |
| Heating extension (2 radiators) | £1,200 |
| Plastering, decoration, flooring | £2,750 |
| Built-in wardrobes (joinery) | £1,400 |
| Contingency used | £550 |
| Total (4 weeks on site) | £16,800 |
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Building Regulations and how long the work takes
Planning permission is rarely needed for an internal garage conversion, but Building Regulations approval always is — and it is the part homeowners most often underestimate. Approval covers structure, fire safety, ventilation, damp-proofing, insulation U-values and electrics, and the fee plus inspections typically runs about £800–£1,100 on a single garage. You can use either your local authority Building Control or an approved inspector.
What the inspector checks
Expect inspections at key stages: the floor build-up and damp-proof membrane before it is covered, the wall and roof insulation before boarding, the infill wall where the up-and-over door was, and a final sign-off. The garage floor usually sits below the house floor and lacks a membrane, so raising, tanking and insulating it to current standards is the single detail most likely to trigger a query. The official Building Regulations approval guidance sets out when and how to apply.
A realistic 2026 timeline
Once drawings and the Building Control application are lodged, a standard single-garage conversion is roughly 3–5 weeks on site: week one for strip-out, floor and damp works, weeks two to three for the door infill, insulation, first-fix electrics and heating, and the final week or two for plastering, flooring, decoration and sign-off. Adding an en-suite or kitchenette adds about a week for plumbing first and second fix.
Common Questions
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