Shared walls with the house
Integral garages already share walls with the house, so they need less new insulation than attached or detached garages.
Built into your house, sharing the walls, roof and services, which makes it the cheapest garage to convert. Read our full cost guide and use the calculator to see what your project would cost.
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Typical all-in prices including labour, materials, insulation, plastering and VAT. Prices vary with garage condition, specification and region.
| Item | Typical Cost | % of Total |
|---|---|---|
| Garage door removal & wall/window | £1,400 | 20% |
| Insulation | £1,600 | 23% |
| Flooring | £1,200 | 17% |
| Electrics | £1,300 | 18% |
| Plastering | £900 | 13% |
| Decoration | £700 | 9% |
| Subtotal | £7,100 | 100% |
These figures cover the main trade and material costs for a standard integral garage of around 15–16m² with a basic-to-mid specification. They exclude the fire-rated wall and door upgrade of £800-£1,800 where the garage shares structure with habitable rooms, building control fees of £300-£900 and damp-proofing if the floor needs raising. This is why the full project cost on this page is £8,000-£15,000. An en suite or higher-spec finish will increase the total cost.
Integral garages already share walls with the house, so they need less new insulation than attached or detached garages.
Power and heating are often close by, so they can connect to the house without long new service runs.
The garage floor may sit below the house floor. If so, it may need raising and damp-proofing.
If the garage contains a boiler, meter or utility connections, moving them adds to the conversion cost.
Fire-rated walls and doors may be needed between the converted room and the rest of the house under Building Regulations.
A basic office or bedroom costs less. An ensuite or premium finish will increase the final price.
An integral garage conversion is unlike any other type because the garage is already part of your home and it shares the house walls, the roof and sometimes a room above it so you are basically converting a space that already exists rather than adding a new building structure. This is why it is considered the most affordable type of garage conversion.
You will also need to take care of a few extra things like fire safety, sound insulation and moving the boiler or electricity meter to a new location and these extra things will cost you separately. This guide explains what makes an integral garage conversion different and what will be your expected budget before you start getting quotes.
Converting an integral garage will cost you between £8,000 to £15,000 but a conversion project with an en suite can cost £20,000 or more. The most common integral garages are 14-18 m²and the average cost is between £600 - £1200 per m². That's lower than most attached or detached garage conversions because a lot of the structure is already part of the house.
There is less building work because the walls, roof and services are already there. Usually the only new exterior wall is the one which replaces the garage door.
The integral garage is basically built into your home already, so there's a lot less structural work than other garage types. Usually you are not creating a bunch of new external walls but just swapping the garage door with a new insulated wall, window or entrance door.
It is also warmer from the beginning as the garage shares walls with the house. Electricity and heating typically are close by as well which can reduce electrical and heating costs versus a detached garage.
The main drawback is that building regulations emphasise more regarding fire safety and sound insulation. Since the new room is part of the home, fire safety and sound insulation needs more attention.
One of the key differences between an integral garage conversion and other types of garages is fire safety. The new room is an extension of the house structure and therefore will be subject to the relevant building regulations.
This normally includes:
If you want to raise an existing wall to the required fire standard, this would cost you between £800 and £1,800 and final cost will be based on how much work is involved.
If your integral garage is adjacent to a neighbour's property then building regulations may require you to add extra sound insulation once you convert it to a habitable room.
This costs range around £400-£900 for building regulations fee and this is something that detached garage conversions do not have to worry about. If you have a bedroom above the garage, improving the sound insulation in the ceiling may be recommended to reduce the impact of noise between floors.
Many integral garages contain a boiler, electricity meter, gas meter or the main stopcock. If these need moving before work can begin, they'll add to the overall cost.
Boiler relocation: £500 to £1,500, depending on the new location and whether pipework or the flue needs changing.
Consumer unit or meter relocation: £400 to £900, although your energy supplier may also need to be involved.
Stopcock relocation: Usually a smaller plumbing job, but worth checking before work starts.
If any of these are in your garage, you should ask the contractor to price them separately in the quote so you would know what exactly is included in the job itself.
Labour
Labour accounts for about 55 to 65% of the overall cost of conversion. Integral garages already have a structure in place so there is less work to be done as compared to other type of garages.
Structural work
| Item | Cost |
|---|---|
| Garage door removal and wall infill | £1,200 - £1,700 |
| Fire-rated wall upgrade | £800 - £1,800 |
| New window and/or door | £1,000 - £1,600 |
| Floor slab upgrade (if needed) | £900 - £1,400 |
Insulation
Integral garages are easier to insulate because they already share walls with your house. You should expect to pay between the range of £1,000 and £2,500 and most of the work will be done on the floor and outside wall where the garage door has been removed.
Electrics and plumbing
Electrical work is usually less expensive because the existing circuits are already nearby in your house and these can cost you between the range of £800 and £1,500. Adding an en suite adds £2,500 to £5,000 to plumbing.
Building regulations and professional fees.
| Item | Cost |
|---|---|
| Building control application | £300 - £900 |
| Lawful Development Certificate (optional) | £124 - £310 |
| Room type | Cost |
|---|---|
| Home office or hobby room | £8,000 - £10,500 |
| Bedroom | £9,500 - £13,500 |
| Bedroom with en suite | £14,000 - £20,000 |
A home office or hobby room is the cheapest option because it doesn't need plumbing and very little structural work. A bedroom costs a little more, while adding an en suite increases the budget because of the plumbing, drainage and ventilation.
| 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 |
An integral garage conversion may cost £11,000 in one part of the UK but can cost you between £12,650 to £13,750 in London or the South East. The same conversion project might be cheaper in other parts of the North, or Scotland and Wales.
A few extra costs are easy to miss when budgeting for an integral garage conversion.
Boiler, meter or stopcock relocation. These are commonly found in integral garages and you will need to move them to another location before work can start.
Fire-rated wall and fire door. These are often overlooked when comparing quotes but are required on integral garage conversions.
Pre-conversion survey (£300 to £600). A survey can inspect uncover structural, damp or fire safety issues before your work starts.
Contingency. Keep aside 10 to 15% of your budget for unexpected work that may need to be done. On an £11,000 conversion, that's £1,100 to £1,650.
Party wall agreement. If your garage shares a wall with a neighbouring property, some structural work may require a party wall agreement.
Insurance. You should let your insurer know once the conversion is complete because you have changed how part of your property is used.
Integral garage conversion vs house extension
Integral garage conversions are one of the cheaper ways to create extra living space in your house. It's a fraction of the cost of building a house extension, costing around £600 to £1,200 per m², as the walls, roof and foundations are already in place.
Does it add value?
A well-finished integral garage conversion can add value to your home because it becomes part of the existing living space. Before converting it, think about whether losing your garage will affect parking or storage.
How to Keep Costs Down
Everything UK homeowners ask us about integral garage conversion costs, planning and building work.
An integral garage shares walls, a roof and other services with the house so there is a lot less new structural work required. This generally reduces costs to £8,000 to £15,000, against £10,000 to £18,000 or higher for a standard single garage of similar size.
Cost to move a boiler is between £500 to £1,500 (depending on distance and if new flueing is required). One of the most often overlooked costs of an integral garage conversion is the boiler as it is often housed here.
It costs between £800 and £1,800 to upgrade an existing wall to the required 30-minute fire resistance standard, based on how much work the separating wall requires. This is a cost unique to integral garages, as they share structure with the house.
If your integral garage is next to a neighbour’s property, as in a semi-detached or terraced house, you will probably need additional sound insulation in the wall you share with them. This costs between £400 and £900, and is not applicable to detached garage conversions.
Attached or detached garages are significantly more expensive, costing from £900 to £1,800 per square metre, whereas integral garage conversions are typically between £600 and £1,200 per square metre due to the shared structure.
Moving a consumer unit or meter will typically cost between £400 and £900 but your energy provider might also have to be involved which can add extra time to your project.
Other than the headline quote, budget for boiler, meter or stopcock relocation if applicable, fire rated wall and door upgrade and a 10 to 15% contingency for unexpected work.
Yes, it is usually the cheapest option for adding habitable space to a UK home, costing £600 to £1,200 per square metre in comparison to £1,800 to £3,000 or more per square metre for a house extension.