Converting an integral garage in the UK typically costs between £10,000 and £14,000, with £12,000 as a realistic mid-point figure for a straightforward single garage in 2026, according to Checkatrade’s 2026 cost guide. That works out to roughly £750 to £1,000 per square metre depending on specification. Whatever the final figure, Building Regulations approval is normally required because you’re creating habitable space.
TL;DR:
- The cost of converting an integral garage in the UK ranges from £10,000 to £14,000, with regional variations influencing the final price.
- A typical conversion involves a mid-range budget of around £12,000 and includes essential upgrades like new flooring, insulation, and a window.
- Major cost drivers include old solid-wall structures, damp issues, and scope changes such as adding bathrooms or moving entrances.
- Building Regulations approval is almost always necessary, with inspections covering insulation, damp proofing, fire safety, and electrical work.
- Most conversions take 2 to 4 weeks for simple projects, but complex builds with structural or plumbing additions can extend to 6–8 weeks.
Table of Contents
- Integral garage conversion cost: low, typical and high-spec price bands
- What’s included in a typical garage conversion quote
- What drives your final price up or down
- Building Regulations and planning permission explained
- How long does a garage conversion take?
- Getting quotes you can actually compare
- Complete Property Solutions: local experience you can rely on
- Why most cost guides miss the point
- Ready to talk about your garage conversion?
- Sources
- FAQ
Integral garage conversion cost: low, typical and high-spec price bands
Where your project lands within that £10,000 to £14,000 window depends almost entirely on specification, not just size. A basic conversion using the existing shell with minimal changes sits at the lower end, while adding plumbing, higher-end finishes or structural alterations pushes you towards the top and sometimes beyond it.
Here’s how the bands typically break down for a single integral garage:
- Low-spec (basic living space): around £10,000 to £11,500, using existing openings and simple insulation
- Typical mid-range conversion: £12,000 to £13,500, including new flooring, insulation to current standards, and a window replacing the garage door
- High-spec conversion: £14,000 upwards, particularly where an en-suite, underfloor heating or bespoke joinery is added
Per-m², expect somewhere between £750 and £1,000 as a sensible guide figure, though this varies with structural condition and finish quality. Homeowners in London and the South East generally see costs at the upper end of any national range, largely down to labour rates, while many parts of the North West, including Warrington, St Helens and Wigan, tend to sit closer to the middle or lower end of UK averages. That regional gap is worth bearing in mind if you’ve been quoting from a national guide that skews southern.
What’s included in a typical garage conversion quote
A proper itemised quote should break the job down clearly rather than giving you one lump figure. Knowing what each line represents helps you compare quotes fairly and spot where corners might be cut.
- Design and drawings: often £300 to £800, covering scaled plans and Building Regulations submission documents
- Structural works: £800 to £2,500 if the garage door opening needs infilling with an RSJ or lintel
- Damp proofing and floor insulation: £1,000 to £2,000, essential given most garage floors sit below the damp-proof course of the main house
- Wall insulation and finishing: £1,500 to £3,000 depending on wall construction
- Windows, doors or garage-door infill: £800 to £2,000
- Electrics, heating and plumbing: £1,500 to £4,000, rising sharply if you’re adding a bathroom or kitchen
- Plastering, flooring and decoration: £1,500 to £2,500
Variability mostly comes down to what’s hiding behind the existing garage walls. Solid brick with no cavity, for example, costs considerably more to bring up to modern insulation standards than a cavity wall does.
What drives your final price up or down
Construction type is often the biggest single factor. Older integral garages, particularly solid-wall builds common across parts of the North West built before the 1970s, need more extensive insulation work to meet current performance standards, and that adds both material and labour cost. Damp issues, uneven floor levels, or a garage that’s structurally tied awkwardly into the main house can all add unplanned expense once work begins.
Scope creep is the other major driver. Adding a bathroom, moving the entrance, or upgrading beyond basic insulation each adds cost incrementally rather than as one big jump.
- Solid versus cavity wall construction
- Existing damp or subsidence issues
- Adding plumbing for a bathroom or kitchenette
- Flooring, glazing and heating specification choices
- Site access for materials and skips
- Conservation area status, listed building consent, or removed permitted development rights, all of which can add design and application time
Pro Tip: Ask your contractor to inspect the garage floor and walls for damp before you finalise a budget. Solid-wall insulation is frequently the single biggest hidden cost on a garage conversion, and it’s far cheaper to plan for it than discover it mid-project.
Building Regulations and planning permission explained
Building Regulations approval is normally required whenever you convert a garage into habitable space, regardless of whether planning permission is needed, according to Planning Portal guidance. Planning permission itself is often not required because most integral conversions fall under permitted development, but exceptions apply, including conservation areas, homes where permitted development rights have been removed, or projects that create a separate dwelling, as government technical guidance sets out. Always confirm with your local planning authority before starting.
On the Building Regulations side, expect scrutiny of:
- Floor U-values around 0.25 W/m²K and wall upgrades to around 0.30 W/m²K, per technical guidance
- Damp-proofing and ventilation provisions
- Escape window sizing where a bedroom is created
- Fire separation and updated smoke alarm coverage
- Sign-off for new electrics, drainage and doors or windows, as outlined in Building Regulations checklists
You can apply via Building Notice or Full Plans. Full Plans gives you approved drawings before work starts, which usually suits more complex jobs, while a Building Notice suits simpler conversions where you’re confident of the standard required.
How long does a garage conversion take?
Most straightforward integral conversions run to a fairly predictable rhythm:
- Survey and drawings: 1 to 2 weeks
- Strip out and structural work: 3 to 7 days
- Insulation, electrics and plumbing: 1 to 2 weeks
- Plastering and finishes: 1 week
- Building control inspection and final certification
A simple conversion typically completes in 2 to 4 weeks, while more complex projects involving bathrooms or structural changes can take 6 to 8 weeks.
Getting quotes you can actually compare
Ask every contractor for an itemised, fixed-price quote, and check precisely what’s excluded, decoration, fixtures and drainage connections are common gaps. Confirm who’s applying for Building Regulations approval and whether inspection fees and the final certificate are included in the price.
- Check trade credentials, such as Guild of Master Craftsmen membership, and insurance cover
- Ask for references and recent photos of similar completed conversions
- Be wary of vague scopes, unusually low prices with no detail, or large upfront payments without a staged schedule
Pro Tip: A quote that’s £2,000 cheaper than everyone else’s is rarely a bargain. It usually means something significant has been left out.
Complete Property Solutions: local experience you can rely on
Garage conversions are best handled with genuine technical understanding and professional experience to ensure quality results. A typical process for a garage conversion project starts with a site survey, followed by a fixed-price quotation and full project management, including Building Regulations support, from start to finish. Building services are typically provided across the North West, including areas such as Warrington, St Helens, Wigan, Great Sankey, Penketh, Culcheth, Lowton, Rainhill and Haydock, ensuring local knowledge of housing stock and typical construction quirks.
Why most cost guides miss the point
Most cost guides treat the garage conversion as a single number to hit, and that’s where homeowners get caught out. The honest picture is that a conversion is really a bundle of separate decisions, floor insulation, wall build-up, whether you want plumbing, and each one has its own price tag that stacks up quietly.
Conventional advice tends to underplay how much the existing structure dictates cost. A solid-wall 1960s garage in Culcheth and a cavity-wall 1990s garage in Penketh can carry genuinely different budgets for the same finished result, purely because of what’s already there. That’s the detail that separates an accurate quote from an optimistic one.
If you take one thing from this guide, prioritise getting the structural survey done properly before fixing a budget in your head. Everything else, tiles, fittings, décor, can flex around that figure. The fabric of the building can’t.
— Gareth
Ready to talk about your garage conversion?
If you’re weighing up a garage conversion against other ways of adding space, our extensions page is worth a look too, but for many homeowners across the North West, converting an integral garage remains the most cost-effective route to extra living space, since the walls, roof and floor are largely already there. Contacting a reputable local building company can provide a free site visit, an itemised fixed-price quote, and clear guidance on Building Regulations from the outset, avoiding vague estimates and surprise extras.
Building professionals typically work across Warrington, St Helens, Wigan, Great Sankey, Penketh, Culcheth, Lowton, Rainhill and Haydock, backed by extensive experience and industry credentials. If your garage has been gathering clutter for a decade and you’re ready to see what it could become, visit our garage conversions page and get your free quote booked in.
Sources
- Garage Conversion Cost 2026 | UK Price Guide
- Garage conversion planning permission guidance
- Garage conversion easy guide (CNC Building Control)
- Permitted development rights technical guidance
FAQ
How much does it cost to convert an integral garage into a room?
Most single integral garage conversions in the UK cost between £10,000 and £14,000, with £12,000 being a typical mid-range figure. The final price depends heavily on whether you’re adding plumbing, upgrading insulation to modern standards, or keeping the specification basic.
What is the typical cost of converting a garage in the UK?
Costs typically fall between £10,000 and £14,000 for a standard single garage, working out to roughly £750 to £1,000 per square metre. Costs tend to run higher in London and the South East, and somewhat lower across much of the North West.
Is a garage conversion cheaper than an extension?
Yes, a garage conversion is generally cheaper than a new extension because the walls, roof and floor slab already exist, cutting out most groundworks and structural build costs. An extension of comparable size can easily cost two to three times more once foundations, brickwork and a new roof are factored in.
Do I need planning permission to convert my integral garage into a room?
Often not, since most integral conversions fall under permitted development, but Building Regulations approval is normally required regardless. Exceptions apply for conservation areas, homes with removed permitted development rights, or conversions forming a separate dwelling, so always check with your local planning authority first.
