Garage Size
Floor area drives most of the cost. Extra usable space typically adds £700 to £900 per m².
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The prices below include labour, materials, insulation, plastering and VAT. Costs vary with the condition of the garage, the level of finish and your location.
| Conversion | Typical size | Cost range (inc. VAT) |
|---|---|---|
| Single Garage | 13–18 m² | £10,000 – £18,000 |
| Double Garage | 28–36 m² | £18,000 – £34,000 |
| Integral Garage | 14–18 m² | £8,000 – £15,000 |
| Detached Garage | 15–20 m² | £16,000 – £28,000 |
| Partial Conversion | 8–12 m² | £6,000 – £12,000 |
| Luxury Conversion | 20–36 m² | £30,000 – £55,000 |
Floor area drives most of the cost. Extra usable space typically adds £700 to £900 per m².
Integral garages cost least to convert. Detached garages need new services, drainage and a full roof upgrade.
Infilling the garage door, adding lintels, raising the floor slab and removing walls add labour and sign-off costs.
Floors, walls and roof must reach current U-values. Insulation and damp-proofing cost £1,500 to £5,000 total.
A standard window and infill wall costs modestly. Bi-fold or French doors can add £3,000 to £6,000 more.
London and the South East typically cost 15 to 25 percent more. Scotland and Wales are often cheaper.
Answer a few simple questions to see an instant itemised estimate covering labour, materials, VAT, project duration and estimated value added.
1. Your garage
2. Project options
Estimated cost range
£14,400 – £18,400
Average project cost £16,400 including VAT
Project duration
4.3 weeks
Value added
£20,500+
Estimates use 2026 UK build-cost data. Final price depends on site survey.
Converting a garage is one of the most affordable ways to create extra living space. You're already starting with the main structure, so it costs much less than building a house extension from scratch.
The price range is very wide for garage conversion projects as there are lots of things to consider while calculating the actual costs. A straightforward single garage conversion might cost less than £15,000, while converting a detached double garage into a self-contained annexe with a kitchen and bathroom can cost £45,000 or more. The final price depends on the size of the garage, its condition and what you want it to become.
Most garage conversions in the UK can cost you between the range of £8,400 to £55,000. For a standard single garage, the cost is between £12,000 to £18,000 on average. The final price of conversion depends on factors like the size of the garage, whether it's integral, attached or detached and the standard of finish you choose.
A cost of a simple conversion with insulation, plastering, basic electrics and flooring sits at the lower end of this range but if you choose to add features such as a bathroom, underfloor heating or bi-fold doors, you will have to pay more.
If you want a rough idea of the price, measure your garage in square metres and use our calculator to get an estimate. It will give you an estimate based on your garage type and the type of finish you chose for the conversion.
Following are the four things that have the biggest impact on the cost.
Garage type. Integral garages are the cheapest to convert because they are already part of the house. The walls, roof and floor are already there and services such as electricity and heating are close by. Attached garages cost more because the external walls need more work to meet current insulation standards. Detached garages are the most expensive because they need things like new water connections, drainage and electrical connections, roofing work and heating.
Size. Bigger garages cost more overall but smaller conversions can be more expensive per square metre because fixed costs, such as building control fees and structural calculations are spread over a smaller space.
Condition. A garage that is dry and in good condition is cheaper to convert than a garage that has damp or damaged roof or a cracked floor. You will see these only after the work has started, which is why you should get a professional survey done before starting the work.
Specification. The finishing specifications you choose can make a big difference to the final price. A basic room with standard electrics, plastered walls and simple flooring costs much less than a conversion with a bathroom, underfloor heating, premium flooring and bi-fold doors. The cost of two garages of the same size can end up thousands of pounds apart because of the specification you chose.
Labour
Most of the cost goes on labour rather than materials. A garage conversion isn't one trade turning up for a few days. You will have builders, electricians, plumbers, plasterers and decorators all working on the project at different stages. Around 60 to 70% of the total cost is labour.
Structural work
Structural work is the biggest part of the job and it covers the work needed to turn a garage into a proper room, including removing the garage door, building the new front wall and adding any structural support that is required.
| Item | Cost |
|---|---|
| Garage door removal & wall infill | £1,300 – £1,800 |
| New window and/or door installation | £1,200 – £1,800 |
| Floor slab upgrade | £1,000 – £1,500 |
| New stud wall | £750 – £1,000 |
| Structural engineer (if load-bearing work is involved) | £500 – £1,200 |
Insulation and damp-proofing
Most garages need extra insulation before they can be turned into a proper living space. The whole garage structure including walls, floor and the roof all need to meet current building regulations. You should expect to pay £1,500 to £5,000 for the insulation, depending on the garage. If there is damp in your garage then you need to get it fixed first before any insulation is fitted and this also increases the cost.
Electrics and plumbing
If you are just adding lights, sockets and a few extra electrical points, it won't cost you much but the price starts to go up once you add plumbing. A kitchenette or basic plumbing costs around £2,500 to £5,000 and an additional bathroom can add an extra £5,500 to £9,000 to the conversion costs.
Building regs & professional fees.
| Item | Cost |
|---|---|
| Building control application | £300 – £1,200 |
| Architectural drawings | £500 – £2,500 |
| Structural engineer's calculations | £500 – £1,200 |
Utility connections
If you have a detached garage then you will need new water lines, drainage and electricity run from the house. These things will cost you between £1,000 to £4,000 depending on the distance from the house itself. You may also need a new consumer unit or a separate heating system which will add to the cost.
Quotes, VAT and payments. Make sure you check your quote for VAT as it makes a huge difference when you are comparing prices. Independent local contractors can be cheaper than larger garage conversion contractors but larger firms can offer longer guarantees or do the whole project for you. Most installers ask for a small deposit first, then stage payments as the work progresses but you should be cautious if you're asked by the contractor to pay most of the money before work starts.
The room you want to create has a big effect on the overall cost. As a guide, here are the average costs for converting a standard single garage:
| Room type | Basic | Mid-range | Premium |
|---|---|---|---|
| Home office / hobby room | £8,000 – £12,000 | £12,000 – £18,000 | £18,000 – £25,000 |
| Bedroom (no en suite) | £10,000 – £15,000 | £15,000 – £22,000 | £22,000 – £30,000 |
| Bedroom with en suite | £15,000 – £22,000 | £22,000 – £32,000 | £32,000 – £45,000 |
| Kitchen / annexe | £20,000 – £30,000 | £30,000 – £40,000 | £40,000+ |
A home office or hobby room will cost you less because there is no plumbing to be installed. A cost for a bedroom is a little more because you need to lay down flooring, windows and do extra finishing work. If you are deciding to add a kitchen or bathroom, the final price will move up because you'll need plumbing, drainage and ventilation. A self-contained annexe costs the most because it includes both a kitchen and bathroom and you may also need extra building regulations approval.
Where you live can make a noticeable difference to the price of conversion. Labour rates vary across the UK and delivery costs for materials can also affect your final price.
| Region | Typical variation |
|---|---|
| London & South East | 15–25% above national average |
| Midlands & East of England | Close to national average |
| North England | 10–15% below national average |
| Scotland & Wales | 5–20% below national average, varies by area |
A garage conversion job that will cost £15,000 in one part of the country could cost £17,250 to £18,750 if the house is in London or the South East. In parts of the North, Scotland and Wales, the same project will cost less than average.
It is always worth getting a few quotes from local builders because prices can vary even within the same area.
Some costs don't appear until work has started and these costs are usually not mentioned in the quotes so make sure to include them in your budget before starting the project.
Pre-conversion survey (£360 to £720). A survey can uncover damp issues, roof problems or structural issues before work begins so you can have a clearer idea of the actual cost.
Contingency. You should always set aside an extra 10 to 15% of your budget for unexpected work. On a £15,000 conversion job, that works out to be around £1,500 to £2,250.
Garage door removal. Many builders include this in the price, but don't automatically assume they will include it and check the quote before you accept it.
Planning permission. Most garage conversions don't need planning permission, but listed buildings, conservation areas and some external alterations may require approval.
Utility connections. Detached garages do need new water, drainage or electrical connections which can increase the costs than you would have expected.
Changes during the build. If the plans need altering to meet building regulations, the project can end up costing more and take longer to finish.
Insurance and your mortgage. Once the conversion is complete, tell your insurance company. If you have a mortgage, it's also worth checking whether your lender needs to be informed.
Online estimates are useful but there is no substitute for a detailed quote. Before you start, make sure you:
Measure your garage. Work out the internal floor area in square metres by measuring the length and width.
Decide how you'll use the space. A home office costs far less than an annexe with a kitchen and bathroom, so this has a big impact on the budget.
Get at least three quotes. Choose builders with garage conversion experience and ask for itemised quotes covering structural work, insulation, electrics, plumbing, building control and finishes.
Check what's included. Make sure the quote covers things like waste removal, building control fees and disposal of the old garage door, so there are no surprises later during the work.
Check whether planning permission is needed. Most garage conversions fall under permitted development but you should confirm that before the work begins.
You can use our instant calculator for a quick estimate based on your garage type, size and the finish you want and then compare quotes from vetted local contractors.
Garage conversion vs house extension
A garage conversion is a much more affordable option than a house extension as the main structure is already there. You are not putting up new foundations and a roof, but just improving an existing space. If your garage is not being used then converting it is one of the cheapest ways to add more living space.
Does it add value?
A well-finished garage conversion can increase the value of your home. The increase in value depends on the property and the local area. One thing to consider is parking because if converting the garage leaves you with little or no off-road parking, it could make the property less appealing to some buyers if you decide to sell your house in the future.
How to keep costs down
Explore costs, timescales and regulations for every kind of garage conversion.
Built into the house, making it the simplest and most affordable type of garage conversion.
View GuideA separate building with plenty of flexibility, though extra utility connections often increase the cost.
View GuideIdeal for creating a home office, bedroom, gym or playroom without extending your home.
View GuideLarge enough for two rooms, an open-plan living space or a layout with a bathroom.
View GuideEverything UK homeowners ask us about garage conversion costs, planning and building work.
Garage conversions come under permitted development so don’t require planning permission. There are however some exceptions that include listed buildings, conservation areas and some projects that change the outside of the property. If you are unsure about it, check with your local council before work starts.
Yes, you will need to get building regulations approval for your garage conversion because you are creating a living space so the he work must comply with regulations for structure, insulation, ventilation, fire safety and electrics.
It can take up to 2 to 4 weeks to complete a standard single garage conversion. Larger projects or conversions with a kitchen, bathroom or structural work can take 6 to 8 weeks.
You can do some of the finishing work yourself, such as decorating or laying flooring. Structural work, electrics and plumbing should be left to qualified tradespeople and signed off under building regulations.
It can affect your home insurance so once the garage becomes living space, you should inform your insurance company so your policy remains up to date.
Yes you can build a room above your garage but keep in mind that it is a much bigger project then a simple garage. It costs more, needs structural work and will often require planning permission as well as building regulations approval.
An integral garage is part of the house. An attached garage connects to the house but it has its own roof. A detached garage stands alone and is not part of the house. Integral garages are the easiest to convert and cost less than other types. Detached garage conversions are costly because they require new utility connections and additional structural work.
Almost always because garage slabs sit lower than house floor level and lack a damp-proof membrane and a new insulated floor can cost between £1,200–£2,800.
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