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How Much Does a Garage Conversion Cost in the UK?
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Garage Conversion Cost intro
How Much Does a Garage Conversion Cost in the UK?
A garage conversion can be one of the most cost-effective ways to create additional living space because the basic structure already exists.
Instead of building entirely new:
- Foundations
- External walls
- Roof
you are adapting an existing space so that it can function properly as part of the home.
A garage conversion may be used to create:
- Home office
- Playroom
- Existing roof structureSnug
- Bedroom
- Utility room
- Gym
- Larger kitchen
- Additional living space
- Accessible ground-floor accommodation
For 2026, a typical UK garage conversion costs around £10,000–£20,000 for a standard 16 m² integral or attached garage, with an average around £15,000. Current Federation of Master Builders guidance puts the average for a standard 16 m² conversion at around £13,500. Checkatrade
The final cost depends on the type and condition of the garage, how the new room will be used, the amount of structural work required and whether plumbing, drainage or significant services need to be added.
At Tholos Architects, we help homeowners assess whether an existing garage can be converted successfully and how it can be incorporated properly into the rest of the home.
Garage Loft Cost explained
Garage Conversion Cost per Square Metre
Current 2026 UK guidance suggests garage conversions typically cost around:
£625–£1,250 per m²
for a standard conversion.
This is considerably lower than building a completely new extension, which typically involves creating:
- Foundations
- Walls
- Roof
- Complete external envelope
from scratch.
However, the cost per square metre can rise significantly where the garage needs:
- Structural repairs
- New roof
- New floor construction
- Extensive insulation
- Plumbing
- Drainage
- Bathroom
- Kitchen
- Significant structural alterations
Typical Garage Conversion Costs
A useful 2026 guide is:
| Garage Conversion Type | Indicative Cost |
|---|---|
| Partial garage conversion | £5,500–£8,500 |
| Integral garage conversion | £10,000–£14,000 |
| Attached garage conversion | £10,000–£20,000 |
| Detached garage conversion | £15,000–£25,000 |
| Double garage conversion | £20,500–£45,000 |
| Typical standard conversion | Around £15,000 |
These figures are based on current UK cost guidance and should be treated as early budgeting figures rather than quotations.
Why Garage Conversions Can Be Cheaper Than Extensions
The main advantage is that much of the building already exists.
A garage may already have:
- Foundations
- Walls
- Roof
- External access
- Basic electrical supply
- New insulation
- External cladding or tiles
- More weatherproofing
A typical extension has to create all of these elements from the beginning.
Current guidance places garage conversion costs around £625–£1,250 per m², compared with approximately £1,800–£3,000 per m² for a typical house extension.
That can make converting underused garage space an attractive alternative to extending.
What Is Included in a Garage Conversion Cost??
A straightforward conversion may include:
- Removal of garage door
- New infill wall
- New window
- Wall insulation
- Floor insulation
- Ceiling insulation
- Electrical work
- Heating
- Plastering
- Internal finishes
- Decoration
Current 2026 guidance suggests a standard basic conversion can involve approximately £5,000–£7,800 of core building work before wider project costs and specification are considered.
The exact scope depends on the condition of the existing garage.
What May Not Be Included?
Possible additional costs include:
- Architectural drawings
- Structural engineer
- Planning application
- Building Control
- New bathroom
- New kitchen
- Drainage
- Meter relocation
- New external openings
- Premium flooring
- Bespoke storage
- External landscaping
- VAT
Always check what a builder’s quotation actually includes.
Integral Garage Conversion Cost
An integral garage forms part of the main house.
These are often among the simplest garages to convert because they may already share:
- Walls
- Roof
- Services
- Internal access
with the main property.
Current 2026 guidance puts a typical integral garage conversion around:
£10,000–£14,000
with an average around:
£12,000
Attached Garage Conversion Cost
An attached garage sits alongside or behind the main house but remains physically connected to it.
Current guidance suggests approximately:
£10,000–£20,000
with an average around:
£15,000.
Cost depends on how easily the garage can be connected to:
- Heating
- Electrical systems
- Plumbing
- Existing rooms
Detached Garage Conversion Cost
Detached garages generally cost more to convert.
Current 2026 guidance suggests approximately:
£15,000–£25,000
with an average around:
£20,000.
They can cost more because services may need to travel further from the main house.
This may involve:
- Electrical supply
- Water
- Heating
- Drainage
- Data connections
The existing building may also have been constructed to a lower standard than an integral garage.
Double Garage Conversion Cost
A double garage provides significantly more floor area and can potentially create:
- Large living room
- Bedroom suite
- Office and utility
- Gym
- Multiple rooms
Current guidance gives approximately:
£20,500–£45,000
depending on whether the garage is integral, attached or detached.
The higher total cost reflects both the increased floor area and potentially greater amounts of:
- Insulation
- Flooring
- Windows
- Heating
- Electrical work
- Finishing
Partial Garage Conversion Cost
You do not always need to convert the entire garage.
A partial conversion can retain some garage or storage space while turning the rest into a habitable room.
Current 2026 guidance puts a partial garage conversion around:
£5,500–£8,500
with an average of roughly:
£7,000.
This can work well where you still need space for:
- Bikes
- Tools
- Storage
- Equipment
but do not need the full garage for a vehicle.
garage Conversion options
Garage Conversion to Home Office Cost
A home office is often one of the simplest garage conversions.
It may require:
- Insulation
- Heating
- Electrical sockets
- Lighting
- Data connection
- Flooring
- Decoration
Because it does not normally require extensive plumbing or drainage, it can remain toward the lower end of the cost range.
Garage Conversion to Bedroom Cost
Turning a garage into a bedroom may involve:
- Improved insulation
- Heating
- Suitable window
- Electrical work
- Flooring
- Fire-safety considerations
If the bedroom also includes an ensuite, costs rise further.
The design also needs to make the converted room feel integrated with the rest of the house rather than like a former garage.
Garage Conversion With Bathroom Cost
Adding a bathroom significantly increases the budget.
Current 2026 guidance suggests a bathroom can add approximately:
£5,500–£9,000
to a garage conversion.
Additional work may include:
- Water supply
- Waste pipes
- Soil connection
- Sanitaryware
- Tiling
- Waterproofing
- Ventilation
- Electrical work
The distance from existing drainage can have a major effect on cost.
Garage Conversion With Kitchen Cost
A kitchen creates an even larger cost increase.
Current guidance suggests adding a kitchen may increase the project cost by approximately:
£15,000–£35,000.
This can include:
- Kitchen units
- Worktops
- Appliances
- Plumbing
- Electrical circuits
- Extraction
- Lighting
- Flooring
If the converted garage is intended to become part of a larger kitchen-dining space, the work may also require structural alterations between the garage and house.
Garage Conversion to Utility Room Cost
A utility room may require:
- Sink
- Washing machine
- Dryer
- Storage
- Plumbing
- Drainage
- Electrical work
- Ventilation
This generally costs more than a simple office conversion but less than a full kitchen in many cases.
Garage Conversion to Gym Cost
A garage can work well as a home gym.
Additional considerations may include:
- Floor loading
- Durable flooring
- Ventilation
- Heating
- Mirrors
- Electrical supply
A simple gym conversion can remain relatively economical if no plumbing is needed.
Garage Conversion to Playroom or Snug
These can be among the simplest conversion types.
The main costs usually relate to making the garage feel like a proper part of the home through:
- Insulation
- Heating
- Natural light
- Flooring
- Decoration
A straightforward room conversion is usually cheaper than creating a kitchen or bathroom.
Converting the Garage Door Opening
One of the most visible changes is usually replacing the garage door.
This may involve:
- Removing existing door
- Constructing new wall
- Adding insulation
- Installing window
- Matching external materials
Current cost guidance puts removal and replacement of the garage door at roughly £1,300–£1,500, with a new door or window opening around £1,200–£1,500, depending on the works required.
Making the Front Look Like Part of the House
A poor garage conversion can look obvious from outside.
The new elevation should consider:
- Brick or render matching
- Window proportions
- Cills
- Head details
- Existing architectural character
Good design can make the conversion appear as though it was always part of the house.
dormer Loft conversion cost
Built-in Storage
The sloping areas beside the dormer can be ideal for:
- Eaves cupboards
- Drawers
- Wardrobes
Custom joinery can maximise otherwise difficult areas.
This can add several thousand pounds depending on the design.
Flooring
Loft flooring may include:
- Carpet
- Engineered timber
- Laminate
- Luxury vinyl
Check whether the builder’s quote includes:
- Supply
- Installation
- Underlay
- Finishing trims
Decoration
Some loft contractors include full decoration.
Others may leave rooms:
- Plastered only
- Mist-coated
- Ready for client decoration
Check the quotation carefully.
Scaffolding Costs
Scaffolding is usually required for dormer construction.
It may need to provide access for:
- Roof removal
- Dormer framing
- Roof covering
- Windows
- External finishes
Costs rise where:
- Access is difficult
- Property is tall
- Scaffold stays longer
- Temporary roof is required
Temporary Roof
Because part of the existing roof is opened, some projects use temporary weather protection.
A temporary roof can add cost but can reduce the risk of rain entering the house during construction.
garage conversion cost
Floor Costs
Garage floors are often lower than the internal floor level of the house.
They may also lack sufficient:
- Insulation
- Damp protection
- Thermal performance
The floor may therefore need:
- New insulation
- Screed
- Raised construction
- New finish
Current guidance gives around £1,000–£1,250 for a typical slab/flooring element within a standard conversion
Wall Insulation
Existing garage walls may not meet the thermal standard expected for habitable accommodation.
They may require:
- Internal insulated lining
- Cavity upgrades
- Alternative insulation solution
The correct approach depends on how the garage was originally constructed.
Roof Insulation
The existing garage roof also needs to be assessed.
A cold garage roof may require substantial improvement before the room becomes comfortable.
This could involve:
- Insulation
- Ventilation
- New ceiling
- Roof repairs
Existing Garage Roof Condition
Before converting a garage, check whether the roof itself is in good condition.
Older garages may have:
- Leaks
- Damaged coverings
- Poor structure
- Inadequate drainage
Repairing or replacing the roof can add significantly to the project cost.
Flat Roof Garage Conversion
Many attached garages have flat roofs.
If the roof is old, the conversion may be a sensible time to improve:
- Roof covering
- Insulation
- Drainage
- Flashings
A roof replacement should be treated as a separate cost from a basic internal conversion.
Heating Costs
A converted garage needs to be comfortable throughout the year.
Options may include:
- Extend existing central heating
- New radiator
- Underfloor heating
- Electric heating
The best solution depends on:
- Existing heating system
- Distance from boiler
- Insulation
- Intended use
Electrical Costs
Electrical work can include:
- Sockets
- Lighting
- Data points
- Smoke alarms
- Heating controls
Current 2026 guidance gives around £90–£100 per additional socket as a basic example, although the complete electrical installation will depend on the project.
Plumbing Costs
If plumbing is needed, cost depends heavily on location.
Current guidance gives approximately:
£1,000–£3,000
for adding pipework in a typical conversion scenario.
A bathroom or kitchen can require considerably more once fixtures and drainage are included.
New Internal Doorway
An integral or attached garage may need a new opening into the main house.
This can involve:
- Cutting through existing wall
- Structural lintel
- New door
- Making good
If the wall is load-bearing, structural input may be required.
Structural Alterations
Some garage conversions require very little structural work.
Others may involve:
- Creating large internal openings
- Removing walls
- Rebuilding the front elevation
- Altering roof structure
- Strengthening floors
The more structural change required, the less useful the basic £625–£1,250 per m² benchmark becomes.
Structural Engineer Costs
A structural engineer may be required where the project involves:
- Load-bearing wall removal
- New structural opening
- Roof alterations
- Building above the garage
- Foundation concerns
Current 2026 guidance gives approximately:
£500–£1,000
for structural-engineering input on typical garage-conversion structural work.
Can the Existing Foundations Be Used?
For a straightforward garage conversion, you may not need to change the foundations.
However, their suitability may need to be checked where:
- New heavy walls are proposed
- Another storey may be added
- Existing structure shows movement
- Original construction is uncertain
A garage designed only for storage or parking should not automatically be assumed suitable for every new structural arrangement.
garage conversion cost
Planning Permission for a Garage Conversion
Planning permission is often not required where the work is largely internal and the garage remains part of the same dwelling.
However, planning permission may be required where:
- Permitted development rights have been removed
- A planning condition requires the garage to remain available for parking
- External alterations are significant
- A detached garage is being converted to separate accommodation
- The property has particular planning restrictions
The original planning permission for newer housing developments is especially worth checking.
Current FMB and Checkatrade guidance both note that many ordinary garage conversions do not require planning permission, although the individual property must still be checked.
Detached Garage to Annexe
Converting a detached garage into self-contained accommodation is different from simply creating another room serving the main house.
A self-contained annexe may involve:
- Bedroom
- Bathroom
- Kitchen
- Independent living facilities
Planning considerations become more significant.
Current guidance notes that a detached garage becoming self-contained accommodation will commonly require planning permission rather than being treated as a straightforward internal garage conversion.
Building Regulations for Garage Conversions
A garage becoming habitable accommodation normally needs to comply with applicable Building Regulations requirements.
These may include:
- Structure
- Fire safety
- Thermal insulation
- Ventilation
- Damp protection
- Electrical work
- Drainage
Current FMB guidance confirms Building Regulations approval is usually required when converting a garage into habitable accommodation.
Fire Safety
The conversion may affect:
- Escape routes
- Smoke detection
- Door requirements
- Separation from other areas
The exact requirements depend on:
- Layout
- Number of storeys
- Intended use
A bedroom may need different consideration from a simple utility space.
Ventilation
Habitable rooms need appropriate ventilation.
This may involve:
- Opening windows
- Background ventilation
- Mechanical extraction
Bathrooms, utility rooms and kitchens have additional ventilation requirements.
Natural Light
One of the biggest design challenges is making a former garage feel like a proper room.
A well-positioned window can improve:
- Daylight
- Views
- Ventilation
- Relationship with the rest of the house
The replacement of the garage door therefore needs to be designed rather than treated purely as a construction detail.
garage conversion Cost
Garage Conversion Architect Costs
Current 2026 guidance suggests architectural drawings for a garage conversion may cost around:
£2,000
as a broad benchmark.
The actual architectural fee depends on:
- Existing property
- Complexity
- Required approvals
- Level of service
Building Control Costs
Building Control fees vary by:
- Local authority or approved provider
- Scope
- Project complexity
These should be included in the total budget rather than assumed to be part of the builder’s price.
VAT
Always check whether VAT is included in:
- Builder quotations
- Professional fees
- Cost guides
A quotation excluding VAT may appear considerably lower than the amount ultimately payable.
Contingency
A simple garage conversion may contain less uncertainty than a major extension, but some contingency is still sensible.
Potential surprises include:
- Poor floor construction
- Roof defects
- Damp
- Inadequate insulation
- Unexpected structural work
- Service alterations
Around 10% can provide a useful early budgeting allowance, with more potentially sensible for an older or poor-condition garage.
garage conversion cost
Can I Convert a Garage for £10,000?
Potentially.
Current 2026 guidance puts £10,000 at the lower end of a typical integral or attached garage conversion.
The project would need to be relatively straightforward, with:
- Existing structure in good condition
- Limited structural changes
- No bathroom or kitchen
- Standard finishes
Can I Convert a Garage for £15,000?
Yes.
Approximately £15,000 is currently a useful average benchmark for a standard UK garage conversion.
This may suit a conversion into:
- Office
- Snug
- Playroom
- Bedroom
depending on the property.
Can I Convert a Garage for £20,000?
Yes.
£20,000 provides more flexibility for:
- Better specification
- More service alterations
- More substantial external changes
- Detached garages
It is also around the upper end of the current standard attached-garage range.
Can a Garage Conversion Cost £30,000 or More?
Absolutely.
Costs can rise above £30,000 where the project includes:
- Double garage
- Bathroom
- Kitchen
- Detached building
- Major structural work
- Roof replacement
- High specification
- Conversion to an annexe
At that point, the project should be costed individually rather than using a standard garage-conversion average.
Garage Conversion vs Extension Cost
If you already have an underused garage, converting it will generally cost less than constructing the same amount of new extension space.
Current broad figures are:
Garage conversion: £625–£1,250 per m²
House extension: £1,800–£3,000 per m²
However, you lose the garage.
The decision therefore also needs to consider:
- Parking
- Storage
- Property layout
- Future use
- Local housing market
Will Losing the Garage Cause a Problem?
Before converting it, consider whether the garage is genuinely underused.
Think about:
- Off-street parking
- Bike storage
- Garden equipment
- General storage
- Future resale
Some properties benefit significantly from the extra internal room.
Others may suffer if parking or storage is already limited.
The decision should be based on the property as a whole.
Partial Conversion Can Be a Good Compromise
Where storage is still important, you may be able to retain the front section of the garage and convert only the rear.
This can provide:
- Useful new room
- Storage
- Bike space
without sacrificing the entire garage.
How Long Does a Garage Conversion Take?
A straightforward garage conversion commonly takes around:
2–4 weeks
according to current UK guidance.
More complicated conversions may take longer where they involve:
- Structural work
- Bathroom
- Significant drainage
- Detached garage
- Extensive rebuilding
- Kitchen
garage conversion cost
How to Reduce Garage Conversion Costs
The most effective way to keep the cost down is to avoid unnecessary complexity.
Possible savings include:
- Keep the room use simple
- Avoid unnecessary plumbing
- Retain existing openings where practical
- Minimise structural alterations
- Keep services close to existing connections
- Use standard windows
- Retain a simple layout
- Avoid over-specification
Use the Existing Structure Properly
The reason a garage conversion can represent good value is because much of the building already exists.
If the design begins adding:
- Large extensions
- New roof
- Major structural openings
- Bathroom
- Kitchen
the cost advantage can quickly reduce.
The design should therefore make intelligent use of what is already there.
Think About How the Room Connects to the House
A garage conversion should not feel like a disconnected room reached through an awkward doorway.
Consider:
- Internal access
- Circulation
- Natural light
- Floor level
- Relationship with adjacent rooms
- Furniture
Sometimes opening the converted garage into another existing room produces a much better result.
Get Comparable Builder Quotes
Builders should ideally price the same drawings and scope.
Check:
- Insulation
- Floor build-up
- Windows
- Heating
- Electrical work
- Decoration
- External making good
- Building Regulations work
Otherwise, one quote may appear cheaper simply because important items are missing.
Garage Conversion Budget Checklist
Your total budget may need to include:
- Architectural drawings
- Planning where required
- Building Control
- Structural engineer where required
- Garage-door removal
- New external wall
- Windows
- Internal access
- Insulation
- Floor upgrade
- Roof work
- Heating
- Electrical work
- Plumbing
- Bathroom or kitchen
- Flooring
- Decoration
- External making good
- VAT
- Contingency
Do not assume the builder’s headline figure includes everything required to make the garage a finished habitable room.
How Tholos Can Help With Garage Conversion Costs
A successful garage conversion is not simply about changing the garage door for a window.
The space needs to work as a genuine part of the home.
At Tholos Architects, we can consider:
- Existing structure
- Layout
- Floor level
- Internal access
- Natural light
- Insulation
- Intended use
- Planning constraints
- Building Regulations
- Budget
together from the beginning.
The aim is to make better use of space you already have without introducing unnecessary construction or cost.
Client experience
"
Lorem ipsum dolor sit amet, consectetur adipiscing elit. We had a vision for our home but no idea how to realise it. Tholos Interiors took complete ownership of the project — every detail was considered, every decision explained. The result exceeded everything we had imagined.
– Lawrence Ipsum, Homeowner · London –
Frequently Asked Questions
How much does a garage conversion cost in the UK?
A typical 16 m² integral or attached garage conversion currently costs around £10,000–£20,000, with approximately £15,000 a useful average benchmark.
How much does a garage conversion cost per m²?
Current 2026 guidance suggests approximately £625–£1,250 per m².
How much does an integral garage conversion cost?
Approximately £10,000–£14,000, with an average around £12,000.
How much does a detached garage conversion cost?
Approximately £15,000–£25,000, with an average around £20,000.
How much does a double garage conversion cost?
Current guidance gives approximately £20,500–£45,000, depending on whether the garage is integral, attached or detached.
How much does a bathroom add to a garage conversion?
A bathroom can add approximately £5,500–£9,000, depending on drainage, specification and plumbing.
Do I need planning permission for a garage conversion?
Often not for a straightforward conversion remaining part of the main home, but planning permission may be required where rights are restricted, external changes are significant or the garage becomes separate accommodation.
Turn Existing Space Into Useful Living Space
A garage conversion can offer substantially more living space without the cost of constructing an entirely new extension.
For 2026, around:
£10,000–£20,000
is a useful broad starting range for a typical integral or attached garage conversion, while detached, double or more complex conversions can cost considerably more. Checkatrade
The most important question is not simply whether the garage can be converted.
It is whether the new space will genuinely improve the way the house works.
At Tholos Architects, we can help assess the existing garage and develop a conversion around the property, intended use and available budget.
Disclaimer
This article is part of a series created by our dynamic marketing team for informational purposes only. While we strive to review all content thoroughly, occasional oversights may occur, even after publication. Therefore, we cannot accept liability for any interpretations or use of the information provided. For the most up-to-date information or to report any discrepancies, please contact us at hello@tholos-architects.com.
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