How Much Does a Garage Conversion Cost in 2026? (UK)
A UK garage conversion in 2026 typically costs £7,000–£18,000 for a single garage and £15,000–£30,000 for a double. Price is driven by use case (simple study vs full bedroom with ensuite), floor build-up (existing slab usually needs a new insulated floor), wall upgrade to Part L thermal standards, and whether you keep or replace the garage door. A basic integral single-garage-to-study conversion sits at £8k–£12k; a double-garage-to-annexe with kitchenette and ensuite can reach £32k+. This is the most cost-efficient extension type per m² on the UK market — £900–£1,400/m² vs £2,800–£4,500/m² for a rear extension.
How much is a garage conversion in 2026?
Typical 2026 UK garage conversion costs by use case:
- Single garage → study / playroom — £7,000–£12,000
- Single garage → bedroom (no ensuite) — £10,000–£16,000
- Single garage → bedroom + ensuite — £14,000–£22,000
- Double garage → open-plan room — £15,000–£24,000
- Double garage → annexe (bed + bathroom + kitchenette) — £22,000–£32,000+
Most integral single garage conversions don\u2019t need planning permission (Class A, B, C Permitted Development), but they all need Building Regulations sign-off for thermal, fire, structural and ventilation compliance.
Garage Conversion Cost by Use Case
What you\u2019re converting the space into matters far more than its footprint. A study is a shell and a socket. A bedroom-with-ensuite is a full waste, supply, fire and thermal build-up. Here\u2019s what each realistically costs in 2026.
Single garage → study / playroom (basic)
Replace the up-and-over door with an insulated stud wall + window, insulate and plasterboard walls and ceiling, lay a new insulated floor build-up over the existing slab, add power + lighting + a radiator off the existing heating loop. Decorated. Most common conversion we see.
Single garage → bedroom (no ensuite)
Same shell as the study, plus higher-spec insulation for Part L habitable room standards, a full fire escape window (1:40 egress), smoke alarms on a mains circuit, two double sockets per wall, and sometimes a small built-in wardrobe recess. Most popular with growing families needing a 4th bedroom without building out.
Single garage → bedroom + ensuite
Adds an internal stud-partitioned shower room — typically 1.2m × 2.0m. Needs a saniflo or pumped waste, hot & cold supply extension off the existing system, MVHR or mechanical extract, and a tiled wet-zone. This is the best-value way to add a self-contained teenager or guest suite.
Double garage → open-plan room
30m² of habitable space — serious room for a home cinema, large home office for two, or living room. Two garage doors infilled with a matching brick course, a 2m-wide window (or bifolds to the garden if it faces the right way), full insulation and Part L glazing.
Double garage → fully self-contained annexe
Full self-contained granny annexe: bedroom, small living/kitchenette, shower room. Often needs a building reg application for a \u201Cchange of use\u201D and sometimes planning permission if the annexe is used independently. Typical for multigenerational families and AirBnB-able home offices.
What Actually Drives Your Final Bill
Two single-garage conversions on the same cul-de-sac can land £8,000 apart — same footprint, very different bill. These are the six factors that explain the spread.
1. Integral vs detached garage
Integral garages (under or attached to the house) share walls, heating and roof with the house — conversion typically costs 15–25% less than detached. Detached garage conversions need independent heating, a fresh electrical supply run from the consumer unit, and a new roof thermal upgrade, adding £3,000–£6,000.
2. Floor build-up
Existing garage slabs are almost always too low and uninsulated. A proper Part L habitable floor needs a DPM, 100mm PIR insulation, 65mm screed and flooring — £1,600–£3,200. If the slab is damaged or has a drain running through it, you may need to dig out and re-pour — add £2,500–£5,000.
3. Replacing the garage door
Infilling a single up-and-over door with matching brickwork and a standard window costs £1,400–£2,400. Double doors (or if you want bifolds): £3,800–£7,000. If the gable is rendered, blending the new brick or render to match adds £400–£900.
4. Heating & insulation spec
Extending an existing gas CH loop for 1–2 radiators: £400–£900. Electric UFH with a new consumer unit feed: £900–£1,800. Wet UFH from the existing boiler (manifold + screed): £2,400–£4,200. If the boiler can\u2019t cope with the extra load, you may need a combi upgrade — add £2,200–£3,500.
5. Adding wet services
No plumbing: baseline. Add a cloakroom/WC: +£2,800–£4,500. Add a full ensuite: +£5,000–£8,500. Add a kitchenette: +£3,500–£7,000. If you need to break out the slab to run waste below floor level, add £1,500–£2,800.
6. Region
London labour runs 28–40% above national average. South East adds 15–22%. Midlands and North sit at the national average. Garage conversions are a great fit for the Midlands and North — most 3-bed semis have an integral garage, and the value uplift per £ spent is strongest outside London.
Garage Conversion Cost by UK Region
Based on real project data from 519 UK towns — typical single-garage-to-bedroom conversion, no ensuite, mid-range spec.
Note: Garage conversions are most common in the Midlands and North, where most 3–4 bed semis have integral garages. In inner London, genuine garages are rare — most are already mini-offices or storage rooms.
Real Project: Integral Single Garage, Leeds LS16
4-bed 1970s semi in North Leeds. Integral single garage (16m²) converted into a 5th bedroom with a built-in wardrobe and full egress window. Completed March 2026.
| Building Regulations application + drawings | £1,150 |
| Door removal, lintel, brick infill + render match | £1,700 |
| New A-rated casement window (egress compliant) | £950 |
| Insulated floor build-up (DPM, PIR, screed, oak floor) | £2,200 |
| Stud wall, 100mm PIR, vapour barrier, plasterboard, skim | £2,900 |
| Ceiling insulation + plasterboard (PIR between joists) | £1,100 |
| Central heating extension + new radiator | £780 |
| Electrics (6 sockets, 2 lights, mains smoke, TV/data) | £1,380 |
| Built-in wardrobe recess (MDF carcass, sliding doors) | £1,450 |
| Decoration (prime + 2 coats, skirting, architraves) | £950 |
| VAT | £1,840 |
| Total (4 weeks on site) | £16,400 |
Valuation uplift: £420,000 pre-works → £455,000 post-works valuation (local estate agent appraisal, April 2026). Net value-add £18,600 after construction costs — plus a fifth bedroom that made the house sellable to larger families in the LS16 catchment.
Common Questions
Related Guides
More cost, planning and how-to guides to help you make the right call for your project.
Rear extension cost 2026
If a garage conversion isn\u2019t enough space, here\u2019s what a rear extension realistically costs.
Read Guide →Loft conversion cost 2026
The other classic way to add a bedroom without extending the footprint.
Read Guide →UK house extension cost 2026
The complete framework for budgeting any UK extension — rear, side, wrap or two-storey.
Read Guide →