How Much Does a Garage Conversion Cost in London?
Real 2026 figures from completed London projects — not guesses. A single garage conversion typically costs £15,000–£25,000. Here's what changes the price and what to watch out for.
rcbGroup projectQuick Answer — 2026 London Garage Conversion Costs
Single garage — basic
£15,000–£22,000
Room only, no en-suite
Single garage — mid-range
£20,000–£28,000
Better spec, storage
Double garage
£25,000–£42,000
Two rooms or one large
⚠️ Ballpark figures only. Actual costs depend on size, condition of existing structure, spec level, and M&E complexity. A detailed estimate requires a site visit.
Garage Conversion Price Breakdown
Figures are London market rates for 2026, based on completed projects by rcbGroup. All figures exclude VAT. Second-fix materials (flooring, furniture, fixtures) are client-supplied unless otherwise agreed.
| Conversion type | Low estimate | High estimate |
|---|---|---|
| Single integral garage — basic room | £15,000 | £22,000 |
| Single integral garage — mid-range | £20,000 | £28,000 |
| Double garage conversion | £25,000 | £42,000 |
| Garage + en-suite addition | £28,000 | £45,000 |
| Garage to habitable bedroom (Building Regs) | £18,000 | £32,000 |
| Detached garage conversion | £22,000 | £40,000 |
Typically Included
- ✓Strip-out of existing garage structure/fittings
- ✓Concrete slab or insulated floor system
- ✓Wall insulation and re-plastering
- ✓Ceiling insulation and plasterboard
- ✓New electrical circuits and sockets
- ✓Heating supply (radiator or underfloor)
- ✓Window and door installation
- ✓Building Regulations application and sign-off
- ✓Structural engineer report (where required)
Standard Exclusions
- ✗Second-fix materials (flooring, paint, light fittings, furniture)
- ✗En-suite plumbing and tiling (priced separately)
- ✗Carpet installation
- ✗External landscaping or driveway alterations
- ✗Planning permission (if required — most don't need it)
- ✗Architect drawings for complex schemes
- ✗Boiler upgrades if current system is undersized
- ✗Garage door removal and facade works beyond standard scope
What Changes the Price
Structural condition
Older garages may need new lintels, damp-proofing, or a new concrete slab. A good contractor will flag this during a site visit — not mid-project.
En-suite addition
Adding a shower room or WC adds £6,000–£12,000 depending on spec and proximity to existing waste runs. Most garage conversions that become bedrooms include this.
Detached vs integral
Detached garages cost more because they need new utility connections (electric, heating, possibly water). Integral garages connect to the main house more easily.
Finish specification
Standard = good quality materials. High-end = custom joinery, underfloor heating, premium fittings. The labour doesn't change much — it's materials that drive the gap.
Insulation type
Building Regs require minimum U-values. Achieving this in older structures may mean thicker wall builds or specialist products — both affect cost and usable floor space.
Garage door opening
The existing opening usually becomes a window + wall or full glazed section. The type of infill — brick, blockwork, or a glazed frame — affects both cost and look.
Planning Permission & Building Regulations
Planning Permission
Most garage conversions in England do not require planning permission — they fall under Permitted Development rights.
Exceptions: conservation areas, listed buildings, Article 4 directions, or where you're extending the footprint. We always check before proceeding.
Building Regulations
Building Regulations approval is always required for a habitable garage conversion, covering: structural integrity, insulation (U-values), ventilation, fire egress, and electrics.
rcbGroup manages the full Building Regs process — from application to final sign-off.
Does a Garage Conversion Add Value?
In most of London, yes — significantly. Converting a garage to a bedroom or home office typically adds 10–15% to property value, often exceeding the build cost. Adding a bedroom (especially with en-suite) has the most impact.
One caveat: parking
In areas where off-street parking is scarce (inner London especially), losing a garage space could reduce buyer appeal. If your road has good street parking or you have a second space, this is rarely an issue. Discuss this with your estate agent before committing.
Get a Garage Conversion Estimate
Use the estimator for a rough budget range before booking a site visit.
Ballpark figures only. A detailed, itemised estimated quotation follows a site visit.
Quick Estimate
Adjust the options to get a quick ballpark — not a quote, but a useful starting point.
Want more detail? Try the full cost calculator →
Independently reviewed
Read what clients say — in full, with our replies — on Checkatrade and Google.
Garage Conversion FAQs
How much does a garage conversion cost in London?+
Do I need planning permission for a garage conversion?+
How long does a garage conversion take?+
Does a garage conversion add value to a property?+
Talk to us about your garage conversion
Tell us about your garage — size, current condition, intended use. We'll respond within a few hours with a realistic budget range and arrange a site visit when you're ready.