Garage Conversion Cost UK (2026): Single, Double & Integral
Quick answer
A garage conversion in the UK typically costs £10,000–£20,000 for a single garage and £20,000–£45,000 for a double in 2026, including fees and VAT. A standard-finish single conversion of about 15m² in the Midlands comes out at around £13,000–£20,000, rising to roughly £16,500–£24,500 in London. That is usually less than half the price per m² of building a new extension.
- Single garage (12–18m²): about £10,000–£20,000
- Double garage (30–36m²): about £20,000–£45,000
- Build cost per m²: roughly £480–£1,230 ex VAT, depending on finish
- Building regulations: always needed; planning permission usually not, unless your permitted development rights have been removed
Want a figure for your own garage? Enter the floor area, finish level and region in our free calculator for an instant 2026 estimate including fees and VAT.
How much does a garage conversion cost in 2026?
Converting a garage is one of the cheapest ways to add a habitable room, because the walls, roof and floor slab already exist. You are mostly paying to make an unheated shell warm, dry and compliant: filling in the door opening, insulating, adding windows, wiring, heating and finishing. The garage type matters most, because it decides how much of that shell needs upgrading.
Published 2026 cost guides broadly agree. Checkatrade puts a typical conversion of a 16m² attached or integral garage at £10,000–£20,000 (average £15,000), MyJobQuote gives an average of £14,500 for a standard conversion, and BestBuilders quotes £8,000–£18,000 for a single garage. Our own calculator, which adds design fees, structural input, building control and VAT, lands in the same place.
| Garage type | Typical size | Typical total cost (2026) | Typical time on site |
|---|---|---|---|
| Integral single garage | 15–18m² | £10,000 – £14,000 | 2–3 weeks |
| Attached single garage | 15–18m² | £10,000 – £20,000 | 2–4 weeks |
| Detached single garage | 15–18m² | £15,000 – £31,000 | 4–8 weeks |
| Double garage | 30–36m² | £20,000 – £45,000 | 4–10 weeks |
| Partial conversion (front kept as storage) | Part of a single | £5,500 – £10,000 | 1–2 weeks |
Garage conversion cost per m²
Most builders price garage conversions as a fixed job, but cost per m² is a useful check on a quote. Our calculator uses the following build-only rates, excluding VAT and fees, before a regional adjustment:
| Finish level | Build cost per m² (ex VAT) | What it usually includes |
|---|---|---|
| Basic | £480 – £660 | Door infill with a window, insulated floor and walls, plasterboard, basic electrics, carpet or laminate, decoration |
| Standard | £660 – £920 | As basic plus better glazing, radiator off the existing system or underfloor heating, more sockets and lighting, quality flooring |
| High-end | £920 – £1,230 | Bi-fold or French doors, bespoke joinery, premium flooring, extra glazing or rooflights, smart heating |
Once design, building control and 20% VAT are added, a standard single conversion works out at roughly £870–£1,300 per m² all-in. That lines up with Checkatrade’s £625–£1,250 per m² and BestBuilders’ £900–£1,200 per m² for a basic habitable room. Compare that with £2,200–£2,700 per m² (ex VAT) for a standard single-storey extension and you can see why converting comes first for many families.
Smaller garages cost more per m², because the door infill, window, electrics and fees are much the same whether the room is 12m² or 18m².
Garage conversion cost by size and finish
| Floor area | Basic | Standard | High-end |
|---|---|---|---|
| 12m² (small single) | £8,000 – £12,500 | £10,500 – £16,500 | £14,500 – £21,000 |
| 15m² (typical single) | £10,000 – £15,000 | £13,000 – £20,000 | £18,000 – £25,500 |
| 18m² (large single) | £11,500 – £17,500 | £15,500 – £23,000 | £21,000 – £30,000 |
| 30m² (double) | £18,500 – £27,000 | £25,000 – £37,000 | £34,500 – £48,500 |
| 36m² (large double) | £22,000 – £32,000 | £30,000 – £44,000 | £41,000 – £58,000 |
Single, double, integral and detached: how the type changes the price
Integral garage conversion
An integral garage sits inside the main footprint of the house, usually with a bedroom above. It is the cheapest type to convert: the walls are often already cavity walls, the room above is heated, and services are close by. Checkatrade and MyJobQuote both put a single integral garage conversion at about £10,000–£14,000. The main extra is fire separation: the door between the garage and the house must normally be upgraded to a fire door during the works, and the ceiling may need checking if there is a bedroom above.
Attached single garage conversion
An attached garage shares one wall with the house but has its own roof, often a flat roof or a lean-to. Expect £10,000–£20,000 for a single garage conversion of this type. The roof is the wildcard: a tired felt flat roof may need replacing and insulating, which can add several thousand pounds. A thin single-skin brick wall will also need a new inner lining or insulated stud wall to meet building regulations.
Detached garage conversion
A detached garage is the most expensive to convert, at roughly £15,000–£31,000 for a single. Every wall is external, the walls are often single-skin, and you may need to dig trenches to bring power, water and drainage across the garden. MyJobQuote estimates utility connections alone at £1,000–£4,000. Detached garages are popular as home offices, gyms or annexes, but if you want somewhere to sleep, building control will look closely at fire safety and escape.
Double garage conversion cost
A double garage conversion typically costs £20,000–£45,000. At the low end you have a basic open-plan family room in an integral double; at the top end, a detached double turned into a self-contained annexe with a kitchenette and shower room. Many owners split a double garage, converting one half into a room and keeping the other half for storage or a utility, which keeps costs nearer to a single conversion.
Garage conversion cost by use
What the room is for changes the budget as much as the garage type. Rooms that need plumbing, drainage or extra structural work cost the most.
| Use | Typical cost (single garage) | Notes |
|---|---|---|
| Home office, playroom or snug | £8,000 – £18,000 | Cheapest: no plumbing. Add data cabling and plenty of sockets |
| Bedroom (no en-suite) | £10,000 – £22,000 | Needs an escape window if the only way out is through another room |
| Bedroom with en-suite | £15,000 – £32,000 | Shower room adds about £5,500–£9,000; a macerator may be needed if drains are far away |
| Utility room | Often at the lower end of the single range | Plumbing for washer, sink and drainage; often combined with storage |
| Kitchen extension into the garage | £15,000 – £35,000 extra for the kitchen | Knocking through to the existing kitchen may need a steel beam and engineer’s calculations |
If the garage is becoming part of a larger kitchen-diner, read our kitchen extension cost guide for kitchen fit-out budgets, which run from about £8,000 for a budget kitchen to £30,000 or more for high-end.
What’s involved in a garage conversion
Every conversion is different, but most follow the same sequence. Knowing what each stage involves helps you compare quotes properly.
- Survey and foundations check. Garage walls were not built to house standards, so building control will want to know that the existing footings can take the new loads. The door infill usually needs its own new footing, as the original opening has none.
- Infilling the garage door. The up-and-over door is removed and the opening built up in matching brick or block, usually with a window. Budget about £1,300–£1,500 for this on its own, or £3,000–£6,000 for the full front wall, lintel, window and door package.
- Damp-proofing. Garage floors often have no damp-proof membrane and sit lower than the house. A new membrane is laid and joined to the wall’s damp-proof course; single-skin walls need extra moisture protection.
- Insulating the floor, walls and roof. The floor is usually raised with insulation and a new screed or timber floor to meet the house level. Walls are lined with insulated plasterboard or a stud wall; the roof or ceiling is insulated too. Insulation and damp-proofing together typically cost £1,500–£5,000.
- Windows and ventilation. New glazing must meet thermal standards, and the room needs background (trickle) ventilation and opening windows.
- Heating. A radiator off the existing boiler is cheapest if it has capacity. Electric underfloor heating costs about £800; a new boiler, if needed, is around £2,400.
- Electrics. New circuits, sockets, lighting and interlinked smoke alarms, certified by a registered electrician. Moving a meter box from inside the garage adds cost.
- Finishing. Plastering, flooring, skirting, doors and decoration.
Cost data from MyJobQuote (July 2026). BestBuilders’ split for a £12,000 single conversion is a useful guide: about 24% on structure and door infill, 26% on insulation and plasterboard, 13% electrics, 9% heating, 10% flooring and 18% on decorating and fees.
Full cost breakdown: fees and extras
| Cost item | Typical cost | Notes |
|---|---|---|
| Build work | £480 – £1,230 per m² (ex VAT) | See the per m² table above |
| Design and drawings | 3–6% of build cost | Some conversion firms include drawings |
| Structural engineer | £300 – £1,000 | Lintels, footings, any knock-through to the house |
| Building control | £400 – £900 | Always required for a habitable room |
| Lawful development certificate (optional) | £274 | Confirms the work is lawful; useful when selling |
| Planning application (if PD rights removed) | £548 | England householder fee from 1 April 2026 |
| Party wall surveyor (if work affects a shared wall) | £1,000 – £3,000 per neighbour | Common with link-detached and terraced garages |
| VAT | 20% | On building work and fees, but not the planning fee |
| Contingency | 10% of build cost | Hidden damp, weak footings or roof repairs |
Garage conversion cost UK: regional prices
Labour rates drive most of the regional difference. MyJobQuote reports London and the South East at 15–25% above the national average, and Northern England, Wales and Scotland at 10–20% below.
| Region | 15m² single, standard finish (all-in) | 30m² double, standard finish (all-in) |
|---|---|---|
| London | £16,500 – £24,500 | £31,500 – £46,500 |
| South East | £15,000 – £22,000 | £28,500 – £42,000 |
| South West & East of England | £14,000 – £21,000 | £26,500 – £39,000 |
| Midlands | £13,000 – £20,000 | £25,000 – £37,000 |
| North of England & Wales | £12,500 – £18,500 | £23,500 – £35,000 |
| Scotland & Northern Ireland | £13,000 – £19,500 | £24,500 – £36,500 |
Real example: integral garage to double bedroom in the South East
This is a modelled example from our calculator, not a quote.
- Project: 16m² integral single garage converted to a double bedroom, door infilled with brick and a window, standard finish, radiator off the existing boiler, no en-suite
- Region: South East
- Build cost: £11,800 – £16,500
- Design and drawings: £350 – £1,000
- Structural engineer: £300 – £1,000
- Building control: £400 – £900
- VAT at 20%: £2,600 – £3,900
- Lawful development certificate: £274
- Estimated total: about £15,700 – £23,500, plus a 10% contingency of roughly £1,200–£1,650
Adding an en-suite shower room would add around £5,500–£9,000. The same room in the North of England would come to roughly £13,000–£19,500.
Garage conversion planning permission and building regulations
Do you need planning permission to convert a garage?
Usually not. The Planning Portal says planning permission is not normally needed when the work is internal and does not enlarge the building. Changing the garage door to a wall and window on an attached or integral garage is normally treated as permitted development too.
The big exception is homes where permitted development rights have been removed. This is common on new-build estates, where the original planning permission often includes a condition keeping garages available for parking. If that condition applies to your house, you will need a full householder application (£548 in England). Check your property’s planning history on your council’s website before you commission drawings. You will also usually need permission if:
- the house is listed (listed building consent) or in a conservation area or Article 4 area that restricts changes;
- you live in a flat or maisonette;
- you want to create a separate dwelling, such as a self-contained annexe let to someone else;
- you are extending the footprint, for example building forward of the garage.
If you think the work is permitted development, a lawful development certificate (£274) gives written proof. Our extension planning permission guide explains how permitted development works in more detail.
Building regulations are always required
Turning a garage into a habitable room is a material change of use, so you must have building regulations approval and get a completion certificate at the end. Inspectors will check:
- a proper footing under the door infill;
- damp-proofing of the floor and walls;
- insulation to current standards (for example, council guidance targets about 0.18 W/m²K for floors and 0.30 W/m²K for existing walls);
- ventilation, including trickle vents and opening windows;
- fire safety, including the door between an integral or attached garage and the house, and smoke alarms;
- an escape window if the room can only be reached through another room;
- electrical safety certification.
Without a completion certificate you may struggle to sell, and the room may not count as a bedroom on the sale particulars.
What affects the cost of a garage conversion?
The condition of the existing structure
Shallow footings, a cracked slab, a leaking flat roof or rising damp can each add thousands. A pre-conversion survey (MyJobQuote estimates £360–£720) can catch these problems before you sign a contract.
Floor level
Garage floors usually sit below the house floor. Raising the floor to match, or stepping it, affects the insulation build-up and the door heights.
Services
Moving a gas or electricity meter, rerouting a boiler flue or adding drainage for a bathroom all add cost. A detached garage needs trenching for every service.
Glazing and doors
Replacing the garage door with a single window is cheapest. Full-height glazing or bi-fold doors look great but cost more and must still meet thermal rules.
Where you live
See the regional table above: London prices run about 25% above the Midlands.
How long does a garage conversion take?
- Design and drawings: 1–3 weeks
- Approvals: building control notice or plans; if planning is needed, allow up to 8 weeks for a decision
- Build: 2–3 weeks for a simple integral conversion, 2–4 weeks for an attached garage, and 4–8 weeks or more for a detached garage or double with plumbing
- Sign-off: final building control inspection and electrical certificate
Sources disagree slightly: Checkatrade gives 2–4 weeks for a typical job, while BestBuilders allows 3–6 weeks for a single and 6–10 weeks for a double or detached garage.
Does a garage conversion add value?
Usually, yes, if it adds a useful room. Checkatrade says a conversion could add up to 20% to a property’s value, and MyJobQuote gives 10–20%. BestBuilders suggests a good-quality conversion returns about £1.20–£1.50 for every £1 spent. The best returns come from turning a garage into a bedroom or an extension of the kitchen-diner in a house that is short of space.
There are two caveats. In areas where parking is scarce, losing a garage can put some buyers off. Also, a garage used for storage often turns out to be more valuable than people realise, so plan where the bikes and tools will go. Ask a local estate agent before you commit.
How to save money on a garage conversion
- Choose a room that needs no plumbing. An office or snug costs much less than an en-suite bedroom.
- Use the existing heating system if your boiler has spare capacity.
- Consider a partial conversion, keeping the front of the garage as storage.
- Get a survey first so you are not surprised by damp or weak footings halfway through.
- Get at least three itemised quotes covering door infill, insulation, electrics, heating, finishes and building control.
- Check your planning history early so you do not pay for drawings twice.
If a conversion will not give you enough space, compare it with a house extension or a loft conversion.
Frequently asked questions
Is it cheaper to convert a garage than build an extension?
Yes, usually by a wide margin. A standard garage conversion costs about £660–£920 per m² to build (ex VAT), compared with £2,200–£2,700 per m² for a standard single-storey extension, because the walls, roof and slab already exist.
How much does a single garage conversion cost?
Most single garage conversions cost £10,000–£20,000 including fees and VAT. An integral garage converted to an office at a basic finish can come in around £10,000; a detached single with an en-suite can exceed £30,000.
How much does a double garage conversion cost?
Typically £20,000–£45,000. Our calculator puts a 30m² standard-finish double at about £25,000–£37,000 in the Midlands and £31,500–£46,500 in London, before any kitchen or bathroom.
Do I need planning permission to convert my garage?
Usually not, as long as the work is internal and the footprint stays the same. You will need permission if your permitted development rights have been removed (common on new-build estates), if the house is listed, or if you are creating a separate dwelling. Building regulations approval is always required.
Can I convert my garage into a bedroom?
Yes. The room must meet building regulations for insulation, ventilation and fire safety, and if it can only be reached through another room it needs an escape window. Ceiling height is not usually a problem in a garage.
Does converting a garage affect council tax?
It can. A conversion that adds a habitable room may lead to your property being reassessed when it is next reviewed or sold. A self-contained annexe may be banded separately.
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Sources and methodology
- Checkatrade, How much does a garage conversion cost? (updated May 2026).
- MyJobQuote, Garage Conversion Cost (updated 9 July 2026).
- BestBuilders, How much does a garage conversion cost in 2026? (UK) (updated 1 September 2026).
- Planning Portal, Garage conversion – planning permission (England, accessed October 2026).
- Eden District Council Building Control, Garage conversion to habitable room guidance note (accessed October 2026).
- National planning application fees for England from 1 April 2026 (householder £548; lawful development certificate £274).
- How we calculate our cost estimates
All prices are guide figures for 2026 and vary with your property, the condition of the garage, your specification and location. Always get detailed written quotes before starting work.