Garage construction cost calculator

How the calculation works

How much does a garage cost to build in the UK?

A garage is one of the more practical additions a UK home can have. Parking pressure in towns and cities, the growing number of owners who want to charge an electric car at home, and the need for secure storage all make one useful. The cost depends on the construction method, the floor area and the extras that sit outside the structure. This calculator keeps those elements apart so you can see where the money goes and compare quotes on a like-for-like basis.

The three construction routes

Prefabricated steel garages are usually the fastest and cheapest way to add covered parking on open ground. The frame arrives in sections, is bolted together on site and sits on a concrete base. The panels are normally insulated composite sheets, which keep the building warm and dry but give a functional rather than decorative look. Erection can take only a few days once the base is ready, which is why this option appeals to people who want a quick result. Before ordering, check that the base is level and sized for the building, because a poor base causes problems that are expensive to correct later.

Brick and block garages are the most common permanent option in the UK. The walls are built from concrete blocks, usually with a brick outer leaf, supported on a reinforced concrete slab. The roof is normally a timber structure covered with concrete or clay tiles, and the finish is rendered or brick. The build takes several weeks on site and depends on the weather, since mortar and render need suitable conditions to cure properly.

Attached garages, built as an extension to the house, cost the most per square metre. They share a wall, roof or foundations with the existing building, so the work includes connecting to the existing structure, matching brick and roof finishes, meeting current insulation requirements under Part L of the Building Regulations, and making sure damp proofing and drainage details work with the house. This route usually requires building regulations approval, often needs planning permission, and normally requires architectural drawings.

What the rate per square metre covers

The rate per m² in the calculator is intended to cover the structure: foundations or slab, walls, roof and basic external finishes. It does not normally cover the garage door, the electrical supply or unusual ground conditions. Ground conditions can change the cost of foundations significantly. A level, firm site with good access is far cheaper to build on than a sloping plot, a site with soft ground, or one that needs removal of poor material. A site investigation or trial hole before you commit to a builder can avoid expensive surprises.

Garage doors are priced separately because the range is wide. An up-and-over manual door is the simplest and least expensive option. An automatic sectional door adds a motor, controls and safety sensors. The product standard BS EN 13241 covers industrial, commercial and garage doors and gates, and the installer should provide the manufacturer's test and handover documents.

The electrical supply covers basic lighting, sockets and, if wanted, preparation for an electric vehicle charger. The cost depends on how far the garage is from the consumer unit in the house, how many circuits are needed and whether the existing supply has the capacity for a charger. Electrical work in a dwelling, including its garage and outbuildings, falls under Part P of the Building Regulations in England and Wales. The work must be carried out by a competent person registered with a scheme or notified to building control. The wiring itself must comply with BS 7671, the IET Wiring Regulations. An EV charger has its own cost and needs a dedicated circuit, which adds to the electrical line.

Planning permission and building regulations

Whether you need permission depends on the size, height, position and use of the garage, and on local planning rules. In England, many outbuildings can be built under permitted development rights set out in the Town and Country Planning (General Permitted Development) (England) Order 2015, but there are conditions on height, distance from the boundary and how much of the garden is covered. Attached garages, and garages that are large, tall or close to a boundary, usually need planning permission. A lawful development certificate can confirm in writing that a proposed building does not need permission.

Building regulations approval is a separate requirement. Some small detached outbuildings are exempt under Schedule 1 of the Building Regulations 2010, but only if they meet the conditions set out there. Attached garages and any work involving structure, drainage, insulation or electrics generally need approval. Scotland applies the Building (Scotland) Regulations 2004 and its own planning rules. Northern Ireland applies the Building Regulations (Northern Ireland) 2012, so check the position with the local council in your area.

If the garage is built on or near a shared boundary in England or Wales, the Party Wall etc. Act 1996 may apply and the neighbour may need to be notified. A short enquiry to the local council's planning or building control team before you appoint a builder is usually the quickest way to confirm the requirements for your property.

Resale value and return on investment

A garage can make a home more attractive to buyers, particularly where on-street parking is limited. The effect on value depends on local demand and the quality of the build, so treat it as a practical improvement rather than a guaranteed return. Compare local sold prices for houses with and without garages before assuming an uplift.

When to use this calculator and when not to

Use the calculator for an early budget, to compare construction types for a given floor area, or to check whether the breakdown in a quote looks reasonable. Do not rely on it as a substitute for a written quote, a site survey or a structural design. It does not account for planning constraints, access restrictions, ground conditions, drainage routes, party walls or the cost of removing an existing structure. The output is only as good as the rates you enter.

Common mistakes

Common mistakes include comparing a steel garage with a brick one on price alone, ignoring the cost of the base for a steel garage, forgetting that the garage door and electrical work are often separate items, and assuming planning permission is not needed because the garage is small. Another frequent error is choosing a floor area that is too tight. A single car needs room to open the doors and get out, so a larger footprint may be needed for storage or a workbench.

Choosing a builder

For a prefabricated garage of modest size, a competent DIYer can often erect the kit by following the manufacturer's instructions. Brick and block construction, concrete slabs, extensions and any electrical work should be done by qualified tradespeople. Ask for at least two or three written quotes that list materials, labour, groundworks, the garage door and the electrical work separately. Check references and trade insurance, and make sure the contract sets out a start date, a completion date and payment stages. Avoid paying a large deposit before any work has started.