How to price garage conversion jobs in the UK (2026 guide)

Garage conversion is consistently ranked as one of the best-value home improvements in the UK — adding habitable space at a fraction of the cost of an extension, with typical return on investment of 100 to 150 per cent of the build cost in added property value according to estate agents. For UK builders, garage conversions represent a steady pipeline of jobs in the £6,000 to £25,000 range that can be delivered in two to four weeks without the ground movement risk of an extension or the structural complexity of a loft conversion. Getting the pricing right is critical: a garage conversion that looks straightforward at survey can conceal damp floors, inadequate foundations, asbestos-containing materials, or drainage conflicts that make it significantly more expensive to deliver properly. This guide covers how to price garage conversions accurately, how to handle the structural and regulatory variables, and how to present quotes that win in a competitive market.

Basic vs Premium Garage Conversion Prices

Garage conversion pricing in 2026 ranges from basic functional conversions through to high-specification home offices, playrooms, gyms, and ancillary accommodation depending on the client's brief and the garage's existing condition. A basic single garage conversion — door replacement, floor screed, insulation to walls and roof, plasterboard, plaster, electrics, and decoration — costs £6,000 to £10,000 for a standard 15 to 20 square metre single garage in good structural condition. A mid-specification single garage conversion with underfloor heating, quality flooring, fitted storage or a kitchenette, and a higher finish level costs £10,000 to £15,000. A premium conversion with bespoke joinery, high-end flooring, a wet room or shower room, and full audio-visual installation can reach £15,000 to £20,000 for the same footprint. A double garage conversion follows a similar quality progression but at a larger scale: basic functional conversion £12,000 to £18,000, mid-specification £18,000 to £22,000, premium £22,000 to £30,000. Detached garage conversions that require new drainage connections, sub-mains electrical supply, and potentially planning permission add £3,000 to £8,000 to any of these figures. Always price the conversion to current building regulations standard as a minimum — any client asking you to skip insulation or damp proof membrane to save money is asking you to deliver a building that will not pass building control inspection and will generate problems for them and for you.

Structural Considerations — Door Replacement, Floor and Damp Proof

The structural condition of the garage is the most important variable in pricing a conversion accurately, and a thorough site survey is non-negotiable before submitting a number. The garage door opening — typically 2.1 to 2.4 metres wide — must be infilled with blockwork, brickwork, or a structural timber frame to create an insulated wall with a new window and, in most cases, a new external door. The infill cost is £800 to £2,000 depending on the opening size, the chosen finish (matching brick vs render vs cladding), and whether a lintel replacement is required. The floor is the most common source of cost surprises: most garage floors are a 75 to 100mm concrete slab laid directly on compacted hardcore with no damp proof membrane and no insulation. To comply with building regulations, the conversion requires a damp proof membrane, a minimum of 70mm rigid insulation, and a new 75mm sand and cement screed or proprietary self-levelling screed over the top. The total floor build-up adds 150 to 200mm to the floor level, which must be checked against the threshold height at the connecting house door and any external drainage gullies. In older garages with settling slabs or signs of damp ingress through the floor, the existing concrete may need to be broken out and replaced before the new build-up is installed: add £800 to £2,000 for this contingency on older properties.

Insulation and Heating — Underfloor, Radiator Extension, MVHR

Insulation is the element that determines whether a garage conversion is genuinely usable as habitable space or whether it remains cold in winter and sweating in summer. Building regulations Part L requires garage conversion walls to achieve a U-value of 0.28 W/m²K or better, and the roof to achieve 0.16 W/m²K. For a standard block-built garage, this typically requires 75mm rigid insulation board on the internal face of the walls, finished with plasterboard on battens or direct-bonded with plasterboard-laminate insulated panel. The existing flat felt roof should be replaced as part of any conversion to ensure adequate thermal performance and remove the risk of leaks: a new warm deck flat roof with 100mm PIR insulation and a single-ply membrane costs £2,000 to £4,000 for a standard single garage. For heating, the most cost-effective option for an integral garage adjacent to the house is to extend the existing central heating circuit with one or two radiators: budget £600 to £1,500 for the pipe run, radiators, and connection to the existing system. Electric underfloor heating under a screed or tile finish is a clean alternative where extending the central heating circuit is not practical: a 15 to 20 square metre single garage heated by electric mat costs £400 to £900 in materials plus installation. Where the conversion is used as a home office or habitable room with limited natural ventilation, mechanical ventilation with heat recovery (MVHR) or a simple demand-controlled extract fan keeps air quality compliant with Part F building regulations: budget £400 to £1,200 depending on the ventilation specification.

Electrics, Lighting and Plumbing

Electrical installation is a significant cost component in any garage conversion and must be carried out by a Part P registered electrician with a building regulations self-certification scheme membership (NICEIC, NAPIT, or similar). A standard electrical package for a single garage conversion — consumer unit spur or new circuit from the house distribution board, double sockets around the perimeter, a lighting circuit with LED downlights or pendants, and an outdoor socket — costs £800 to £1,500. If the client wants USB sockets, data cabling for home networking, a wall-mounted TV position with concealed cabling, or hardwired smoke and heat detectors beyond the minimum required, add £300 to £800. Where the garage conversion includes a kitchenette or wet room, plumbing adds a further £800 to £2,500 depending on the distance from the existing stack, the complexity of the drainage connection, and the specification of the sanitary ware and kitchen fittings. A compact wet room with a shower tray, basin, and WC — popular in garage conversions used as ancillary accommodation or home gym spaces — costs £1,500 to £3,500 for the plumbing and waterproofing work alone, before tiles and fixtures. Be clear in your quote about what plumbing scope is included and what the client is supplying separately, particularly sanitaryware and kitchen units where client preference varies enormously.

Planning Permission — When You Do and Don't Need It, and Building Regs

Most integral and attached garage conversions in England fall within permitted development and do not require planning permission — the conversion does not involve an extension of the building footprint and is therefore not considered development requiring consent. However, planning permission is required where the garage is detached from the house and the conversion changes its use to a separate dwelling (including any form of self-contained accommodation), where the property is in a conservation area or Article 4 direction removes permitted development rights, where the property is listed, or where local planning conditions on the original house planning consent specifically restrict garage use. Always check the planning history of the property and the local authority's Article 4 direction map before confirming to the client that planning is not required. Building regulations approval is required for all garage conversions in England and Wales, regardless of planning status — this covers the structural, thermal, fire safety, ventilation, and electrical elements of the conversion. You can either submit a full plans application before starting (more predictable, better for mortgaged properties and subsequent sale) or a building notice at the start of works (faster, suitable for simpler conversions). Building control fees for a typical garage conversion are £300 to £700 depending on the local authority. The building control completion certificate is essential for the client when they come to sell or remortgage the property.

Quoting Tips and Winning Garage Conversion Work

Garage conversion clients are typically homeowners investing £8,000 to £20,000 in a project they plan to use for years, and they make purchasing decisions based on trust and confidence as much as price. A quote that clearly explains what is included — right down to the type of insulation, the screed specification, the electrical standard, and the building regulations process — signals professionalism and protects you from scope disputes later. Break the quote into phases that mirror the build sequence: preparation and structural work, floor and insulation, roof, electrics first fix, plumbing first fix, plastering, second fix and fit-out, and decoration. This gives the client a clear picture of how the project will unfold and makes it easier to discuss value-engineering options if the headline price is above their budget. Common value-engineering points are the floor finish (client lays their own flooring over your screed), decoration (client decorates after practical completion), and sanitary ware supply (client sources their own to your spec). Be explicit about what building regulations require and what is therefore not negotiable — insulation, damp proof membrane, and electrical certification cannot be skipped on a compliant conversion. Following up three to five days after submitting a quote with a brief call to ask if the client has any questions converts a meaningful percentage of undecided clients who simply needed a prompt.

Trade2Base for Garage Conversion Quoting and Project Management

Trade2Base lets builders create detailed, phased quotes for garage conversion projects in minutes — with line items for each trade element, clear descriptions of what is included at each stage, and a branded client portal where the homeowner can review, approve, and pay deposits online. The quote-to-job conversion tracks which jobs were quoted and won, giving you an accurate picture of your conversion rate and which job types are most profitable to pursue. Stage payment schedules are set up at quote stage and collected automatically as each project milestone is reached, so your cash flow matches your build programme rather than lagging behind it. Building control documentation and certificate storage keeps all compliance paperwork against the relevant job record, making it easy to share with clients at practical completion.