garage conversion cost

Quick Answer: Converting a garage into living space costs between £8,000-£25,000 in 2026, depending on specification and finishes. Most garage conversions don’t require full planning permission (thanks to permitted development rights), but you’ll still need Building Regulations approval for structural alterations, damp proofing, insulation, and electrical work. Typical projects take 4-8 weeks from start to finish, and can add 10-15% to your property value when done properly. Why Convert Your Garage in 2026? Garage conversions have become one of the most cost-effective ways to add living space to UK homes without the expense and complexity of a full extension. With average house prices continuing to rise and moving costs sky-high, adding a bedroom, home office, or granny annexe to your existing footprint makes financial sense. The beauty of a garage conversion is that the basic structure already exists. You’ve got four walls and a roof — the expensive bits of any building project. What you’re really doing is upgrading an uninsulated, unheated storage space into a comfortable, thermally efficient room that meets current Building Regulations. In Kent specifically, we’re seeing huge demand for garage conversions as more people work from home permanently. That cold, damp garage that stored garden furniture and old paint tins can become a dedicated office, gym, or guest suite without eating into your garden space. Planning Permission vs Building Regulations: What You Actually Need Here’s where most homeowners get confused. Let me break down the difference between planning permission and Building Regulations approval — they’re not the same thing, and you’ll almost certainly need one of them. Planning Permission for Garage Conversions Good news: most garage conversions fall under permitted development rights, meaning you don’t need formal planning permission. According to the Planning Portal, you can convert your garage without planning permission if: The garage is attached to the house or within the original property boundary You’re not creating a separate dwelling (no self-contained kitchen and bathroom) The property isn’t a listed building or in a conservation area You’re not making major external alterations to the street-facing elevation However, you’ll lose permitted development rights if you want to build an extension in future where the garage once stood. Something to consider if you’re planning longer-term. Building Regulations: Always Required Even if you don’t need planning permission, you’ll always need Building Regulations approval for a garage conversion. This covers structural changes, insulation, ventilation, fire safety, and electrical work. Your local authority will want to see plans and inspect at various stages. Pro Tip: Apply for Building Regulations approval before starting work. The application fee typically costs £400-£600, but getting caught doing unapproved work can lead to enforcement notices and difficulty selling your property later. Building Control inspectors will check foundations, damp proof courses, insulation values, and structural calculations. Garage Conversion Costs in 2026 Right, let’s talk money. Garage conversion costs vary massively depending on specification, but here’s a realistic breakdown of what you’ll pay in Kent and across the UK in 2026. Conversion Type Typical Cost Range What’s Included Basic Conversion £8,000-£12,000 Insulation, plasterboard, basic electrics, vinyl flooring, standard windows Mid-Range Conversion £12,000-£18,000 Plus underfloor heating, plastered walls with skim coat, engineered wood flooring, double glazing upgrade High-End Conversion £18,000-£25,000+ Plus ensuite bathroom, bi-fold doors, vaulted ceiling, high-spec finishes, integrated storage Cost Breakdown by Trade Understanding where your money goes helps you budget accurately and spot dodgy quotes. Here’s what professional tradesmen typically charge for garage conversion work in 2026: Building Regulations and drawings: £600-£1,200 Structural work (RSJ installation if removing door): £1,500-£3,000 Damp proofing and floor insulation: £1,200-£2,500 Stud walls and insulation: £800-£1,500 Plastering (walls and ceiling): £1,000-£2,000 Electrical work (sockets, lighting, consumer unit): £800-£1,500 Heating (radiators or underfloor): £600-£2,000 Windows and doors: £1,500-£4,000 Flooring: £500-£1,500 Decoration: £400-£800 These are Kent prices based on current rates. London and the South East will be 15-25% higher; northern England typically 10-15% lower. The Garage Conversion Process: Step-by-Step Let me walk you through exactly what happens during a professional garage conversion. We’ve done dozens of these projects, and the process follows a pretty standard sequence. Stage 1: Planning and Design (Weeks 1-2) Before any hammer hits a wall, you need proper plans. This isn’t just drawings for Building Control — it’s thinking through exactly what you want from the space. Home office? Guest bedroom? Playroom? The use determines the specification. A good architectural technician will produce drawings showing the new layout, window positions, radiator locations, and electrical points. These get submitted to Building Control along with structural calculations if you’re removing the garage door opening (which almost always requires a steel beam). Stage 2: Structural Work (Week 3) If you’re bricking up the garage door opening, you’ll need an RSJ (rolled steel joist) installed to support the load above. This is notifiable work that Building Control will inspect. The steel lintel typically spans the full width of the opening, sitting on padstones at either end. Most garages have lightweight single-skin walls that aren’t suitable for habitable rooms. You’ll often need to build an inner stud wall with insulation to bring thermal performance up to Building Regs Part L standards (U-value of 0.18 W/m²K for walls). ⚠️ Warning: Never remove a garage door without installing proper structural support above. We’ve seen DIY garage conversions where homeowners simply bricked up the opening without an RSJ, and cracks appeared in the masonry above within months. This is dangerous and expensive to fix retrospectively. Always get structural calculations done by a qualified engineer. Stage 3: Damp Proofing and Floor Preparation (Week 4) Garage floors are rarely suitable for living spaces as-built. They’re usually just a concrete slab with no damp proof membrane (DPM) underneath. You’ve got two options: Dig out and re-lay: Excavate 150-200mm, install 50mm of compacted hardcore, 100mm concrete slab with DPM sandwiched between, then 100mm of insulation topped with 65mm screed. This brings you up to current Building Regs but reduces ceiling height. Build up: Install a DPM directly onto the existing concrete, then insulation boards, then a floating