Garage Conversion Cost UK
A garage conversion is one of the most cost-effective ways to gain extra room at home. Homeowners commonly turn a garage into an office, spare bedroom, playroom, utility room, gym or additional living area — without building a completely new external shell.
Because much of the structure already exists, garage conversions can be quicker and less disruptive than a new extension. However, a garage still needs to be made suitable for habitation. Typical work may include insulation, damp protection, floor build-up, heating, ventilation, windows, electrics, fire safety and Building Regulations compliance.
Every price on this page is a broad UK planning range, not a quotation. Use it to sanity-check your budget, then get itemised quotes from local trades.
Estimate your garage conversion cost
Calculate My Garage Conversion CostGarage conversion cost summary
Typical integral or attached single garage
£10,000 – £22,000
Wider project range
£7,000 – £32,000
Broad planning allowance
£800 – £1,800 / m²
On-site construction (straightforward)
~3 – 6 weeks
Building Regulations approval
Normally required
Garage conversions do not price as neatly per square metre as new extensions. The condition of the existing floor, walls, foundations and roof can have a disproportionate effect on the budget, so two similar-looking garages can cost very different amounts to convert.
| Project | Typical planning range |
|---|---|
| Integral single garage conversion | £9,000 – £16,000 |
| Attached single garage conversion | £11,000 – £22,000 |
| Detached single garage conversion | £18,000 – £32,000 |
| Double garage conversion | £20,000 – £45,000 |
| Partial garage conversion | £6,000 – £12,000 |
| Garage converted into an office or bedroom | £10,000 – £24,000 |
| Conversion with WC, shower room or utility plumbing | £18,000 – £35,000+ |
- These are broad UK planning ranges, not quotations.
- VAT treatment depends on the contractor and quote.
- Professional fees, abnormal structural repairs, high-end fixtures and significant service alterations may be additional.
- London and parts of the South East can sit above the national ranges.
- A smaller project can have a higher cost per square metre because many fixed tasks are still required.
Cost per square metre
A broad planning allowance for a UK garage conversion is roughly £800 to £1,800 per m².
Floor area alone is not enough to produce a dependable estimate. Two 16 m² garages can cost very different amounts where one has a sound insulated slab and existing services while the other needs floor excavation, drainage, structural repairs and new utility connections. For a broader benchmark, see our UK renovation cost-per-square-metre benchmarks.
Costs by garage type
Integral garage conversion
An integral garage sits within the main footprint of the house. It will often have easier access to heating, electricity and internal circulation, although insulation, fire separation and floor levels still need checking.
Range: £9,000 – £16,000.
Attached garage conversion
An attached garage shares at least one wall with the house. Opening it into an existing room may require structural calculations and a supporting beam.
Range: £11,000 – £22,000.
Detached garage conversion
Costs are commonly higher because electrical, heating, water and drainage connections may need to cross the garden or driveway. The roof, walls and foundations may also need more extensive upgrading. A detached garage does not automatically require planning permission — the answer depends on your specific property and how it is used.
Range: £18,000 – £32,000.
Double garage conversion
A double garage can become one larger room or be divided between living space and retained storage. Larger openings, extra services and additional finishes push budgets up quickly.
Range: £20,000 – £45,000.
Partial garage conversion
Homeowners can retain the garage door and front storage section while converting the rear into an office, utility room, WC or small living space.
Range: £6,000 – £12,000.
Intended room and cost impact
The room you plan to create has a large influence on cost. Typical uses include:
- Home office
- Playroom or snug
- Home gym
- Utility room
- Downstairs bedroom
- Bedroom with ensuite
- Kitchen or kitchenette
- Shower room or WC
Offices, playrooms and gyms are generally simpler because they may not need drainage or specialist extraction. Bathrooms, utility rooms and kitchens cost more because of plumbing, waste connections, ventilation, waterproofing, electrical zones, fixtures and fitted furniture. For projects that need drawings or structural design, you can also estimate the likely cost of drawings and professional design services.
What a standard conversion normally includes
- Initial structural and condition checks
- Removing or retaining the garage door
- Constructing an insulated infill wall
- Adding a window or external door
- Damp protection
- Insulating walls, floors and ceilings
- Raising or rebuilding the floor where required
- Heating
- Additional electrical circuits, sockets and lighting
- Ventilation
- Plastering
- Basic joinery
- Decoration and flooring
- Building Control inspections where included in the contractor’s scope
Scope differs between contractors and should always be confirmed in writing.
Common exclusions
- Planning or lawful-development applications
- Building Control fees
- Architect or technician drawings
- Structural engineer calculations
- Drainage alterations
- Relocating gas or electricity meters
- Consumer-unit upgrades
- Asbestos surveys or removal
- Party wall surveyor costs
- Bathroom and kitchen fixtures
- Bespoke storage
- Premium flooring
- Final decorating
- Waste skips
- VAT
Indicative work-package allowances
| Work package | Broad allowance |
|---|---|
| Garage-door removal and insulated infill wall | £1,500 – £3,500 |
| New window or external door | £1,000 – £3,000 |
| Insulated floor build-up | £1,500 – £4,000 |
| Wall and ceiling insulation | £1,500 – £4,500 |
| Electrics, lighting and additional sockets | £1,000 – £3,000 |
| Heating connection or electric heating | £800 – £3,000 |
| Plastering and basic decoration | £1,500 – £4,000 |
| Plumbing and drainage additions | £2,500 – £8,000+ |
These work packages overlap and must not simply be added together as though they were an itemised quotation.
What affects garage conversion costs
- Integral, attached or detached construction
- Single or double garage size
- Existing structural condition
- Foundation and floor-slab condition
- Single-skin walls
- Damp and water ingress
- Roof condition
- Required floor-level changes
- Distance from utilities
- Need for drainage
- New openings or load-bearing-wall removal
- Intended room use
- Window and door specification
- Heating choice
- Finish level
- Regional labour rates
- Access and parking restrictions
- Whether the garage is beneath another room
- Listed-building or conservation constraints
Additional budget items
- Measured survey and drawings
- Architect or architectural technician
- Structural engineer
- Planning application or lawful-development certificate
- Building Control application
- Party wall advice where relevant
- Drainage survey
- Electrical consumer-unit work
- Boiler or heating upgrades
- Asbestos survey on older garage materials
- Alternative storage
- Replacement parking arrangements
- A contingency allowance
Read our guide to hidden renovation costs that are often missed during early budgeting, and if you are considering a garage conversion as part of a wider project see our full house refurbishment cost guide.
What should be included in a quote?
- Exact scope and drawings
- Structural work
- Garage-door infill
- Foundations where needed
- Damp treatment
- Floor construction
- Insulation specification
- Windows and doors
- Electrics
- Heating
- Plumbing and drainage
- Ventilation
- Fire-safety work
- Plastering
- Flooring
- Decoration
- Waste removal
- Building Control liaison
- Start date and estimated duration
- Payment stages
- Guarantees
- VAT
- Explicit exclusions
Tip: a substantially cheaper quote may simply exclude insulation, Building Control work, flooring, heating or final finishes.
Typical project sequence
- Assess how the room will be used
- Inspect the structure, slab, roof and damp condition
- Confirm planning and Building Regulations requirements
- Prepare drawings and structural calculations where required
- Obtain itemised quotes
- Complete structural and external-envelope work
- Install insulation and floor build-up
- Complete first-fix electrics, heating and plumbing
- Carry out plastering and second-fix work
- Finish flooring, decoration and inspections
- Retain completion certificates and guarantees
Timescale
- Straightforward integral conversion: around 3 to 6 weeks on site
- Conversion involving plumbing or structural openings: around 5 to 8 weeks
- Detached, double or high-spec conversion: around 6 to 10 weeks or longer
Total project programmes can be longer because surveys, drawings, approvals, contractor availability and product lead times happen before work begins. Do not assume a fixed duration.
Planning permission
For a house in England, planning permission is not usually required where:
- The work is mainly internal
- The building is not enlarged
- The garage remains ancillary to the main home
Permission or further advice may be needed where:
- The conversion creates an independent dwelling
- The property is listed
- It is in a conservation area or another designated location
- Permitted development rights have been removed
- A planning condition requires the garage to remain available for parking
- The external appearance changes significantly
- The building is enlarged
- The property is a flat, maisonette or another building without normal householder permitted-development rights
This Planning Portal summary relates principally to England. Homeowners in Wales, Scotland and Northern Ireland should consult the relevant local planning authority or building-standards service. This content is general guidance, not legal advice.
Building Regulations
Converting a garage, or part of a garage, into habitable accommodation will normally require Building Regulations approval. Typical areas reviewed include:
- Structural stability
- Foundations for a new garage-door infill wall
- Damp protection
- Floor construction
- Wall, floor and roof insulation
- Ventilation
- Fire safety
- Escape provisions
- Drainage
- Electrical safety
- Heating
- Windows and doors
Planning permission and Building Regulations are separate systems. Needing one does not remove the need to consider the other.
Garage conversion versus extension
A garage conversion can cost less and cause less disruption than a new build because much of the shell already exists. However, it produces only the space already occupied by the garage and may remove valuable parking or storage. If you need more overall floor area, it may be worth comparing costs with a house extension, or exploring alternative ways to gain another room without taking garden space, such as a loft conversion.
Can you DIY a garage conversion?
Homeowners may be able to complete decorating, basic joinery or flooring themselves, but structural alterations, electrical work, gas work, drainage, waterproofing and Building Regulations compliance require appropriate expertise. A full garage conversion is not a suitable beginner DIY project.
Is a garage conversion worthwhile?
- How frequently the garage is genuinely used for parking
- Availability of off-road parking
- Loss of storage
- Local parking pressure
- Whether the new room solves a long-term need
- Quality of the connection to the main house
- Heating and comfort
- Whether future buyers in the area value garages
- Cost compared with moving or extending
Homeowner checklist
- • Is the garage integral, attached or detached?
- • What will the new room be used for?
- • Is the structure dry and sound?
- • Does the floor need rebuilding or raising?
- • Are plumbing and drainage required?
- • Will a structural wall be altered?
- • Are parking or planning restrictions attached to the property?
- • Has Building Control been consulted?
- • Are drawings or calculations required?
- • Does the quote include insulation, heating and finishing?
- • Is VAT included?
- • Has contingency been allowed?
- • Where will existing garage storage be moved?
Sources & Methodology
Pricing on this page is informed by a mix of public macro benchmarks and RenoCost's own datasets and assumptions, listed below. See the Method Glossary for definitions of the terms used.
- Federation of Master Builders — Garage conversion costs UKTrade-association guidance on typical UK garage conversion pricing. Used as a homeowner-facing cross-check.
- Planning Portal — Garage conversion planning permissionOfficial planning guidance on when a garage conversion may or may not require permission (principally England).
- Planning Portal — Garage conversion Building RegulationsOfficial summary of the Building Regulations areas reviewed when converting a garage into habitable space.
- GOV.UK — Building regulations approvalGovernment reference for how Building Regulations approval works in England and Wales.
- RenoCost — UK Renovation Cost Index 2026RenoCost's current-year planning benchmarks, reviewed against published UK cost guidance and used to calibrate 2026 pricing across the calculators and guides.
- RenoCost garage conversion cost assumptionsThe published material and labour assumptions behind the garage conversion module, reviewed against current UK supplier and merchant pricing.
External benchmarks above are used only as macro reference points. None of the organisations listed has reviewed, endorsed, validated or partnered with RenoCost. Specific cost figures on RenoCost reflect RenoCost's own per-module assumptions and completed calculator estimates, and should not be attributed to any external body.
How We Calculate Costs
RenoCost estimates are calculated from published UK cost benchmarks and RenoCost's documented per-module cost assumptions. The model adjusts these assumptions using the property characteristics, selected renovation scope, finish level and broad postcode-based pricing region, then presents a low, mid and high planning range.
- Published UK benchmarks — macro reference points for construction costs and materials and labour trends, used to sense-check RenoCost's own assumptions.
- RenoCost's per-module assumptions — cost and duration assumptions for each renovation module, reviewed and updated periodically by the RenoCost team.
- Estimate ranges — low, mid and high bands set to reflect the realistic spread between competitive and premium specifications, rather than a single fixed price.
Data confidence note
Completed calculator estimates are used to produce anonymous renovation-planning insights. They are not contractor quotations, invoices or confirmed final project costs. RenoCost estimates are intended for initial planning and budgeting. Property condition, specification, access, contractor availability and site-specific requirements can change the final cost. Always obtain detailed written quotations before committing to a project.
Regional adjustments are applied based on postcode area to reflect broad differences in local labour and material rates. See our Method Glossary for definitions of the terms used here.