How much does a garage conversion cost?

The average cost of a single garage conversion (18 sqm) is £16,245 - £22,700

Low cost
Average cost
High cost
How much does a garage conversion cost? graph showing high and low prices for garage conversion

Things to consider

  • Are you looking for a single or double garage conversion?
  • Is any demolition required?
  • Does your conversion require stud walls?
  • Does it need alterations to the floor or roof?
  • Do you need plumbing or electrical work?
  • Are you planning a basic or premium finish?

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Garage conversions – what you’re paying for


Moving home is expensive, and it can be stressful too. That’s why many homeowners pay for garage conversions – which are often a cheaper and easier way to add extra living space to your home and boost its value.

Many of us use our garage for little more than storage, so transforming the room into an extension of your home can make a big impact – creating a bigger living space, another bedroom, or an office. It can also add significant value to your property. These popular projects are often simpler than loft conversions and can be completed in a matter of weeks.

This guide outlines the likely cost of garage conversions and explores the different things you’ll need to consider.


How much does a garage conversion cost per square metre?


The average cost per square metre for a garage conversion is £1,000.

The cost to convert a garage depends on its size and whether it’s inside the house, attached or detached. If it’s detached, you’re also likely to need planning permission for the work. With costs often calculated per square metre, the price difference between a single and double garage conversion can range. As a guide, you can expect to pay an average of £1,000–£1,300 per square metre for a basic conversion. A tradesperson will be able to provide a quote for the work based on the dimensions of your garage, plus other factors such as any structural work and materials that are required.

If your garage has any work benches or other fixtures, they’ll need to be removed, and if there are partition walls, minor demolition work will be required. This contributes to the overall project cost. Foundations may need reinforcing, and if the floors, walls or roof have deteriorated, repairs and remedial work may increase the overall cost too.


How much does it cost to install a stud wall?


The average cost of building a stud wall is £800.

For most garage conversions, foundations and the building of blockwork walls won’t be necessary – helping to keep the overall costs lower than a regular extension. However, to create multiple rooms or achieve the layout you’re looking for, you may need to install stud walls.

You’ll want to factor in the cost of sufficiently high-quality insulation to your budget. Insulation in your stud walls will vastly improve the energy efficiency of the new space and to comply with building regulations, the roof, floor, windows, and walls in your garage conversion will all need to adhere to certain insulation standards. It’s important that insulation is installed properly, otherwise you can end up with a cold and damp room.


How much does flooring cost for a garage conversion?


The average cost of flooring for a garage conversion is £1,300.

Your original garage floor will often be lower than the floor level in your house. So, to avoid a step down into the converted space, you’ll need to raise the floor. This will require a new concrete layer or screed to be added, before carpet, tiles or an alternative flooring of your choice can be laid. During this work you can add insulation to the floor using appropriate materials, such as multi-foil or polystyrene sheets. Different materials can be used to control the height of the floor.

With your floor raised to the required level, you can then select the carpet, tiles or wooden flooring to best suit the type of room your conversion will become. Kitchens or bathrooms will usually be tiled or have a water-resistant wooden or laminate floor. If you’ll be using your conversion as a living space or study, the flooring you choose can be led entirely by your personal preference.


How much does plumbing work for a garage conversion cost?


The average cost for plumbing in a garage conversion is £2,000.

If you’re planning to install a kitchen or bathroom in your conversion, you’ll need to make sure it has a water supply. You’ll also need radiators – no matter how you’re planning to use your converted space – so your central heating will need to be connected to the garage too. A qualified plumber or heating engineer will be able to assess the level of work required to feed the garage.

Connecting your water requires both a mains supply and waste water pipes. Costs will hinge on how much internal plumbing is required to connect up the garage to the mains supply, and then how many items such as toilets and sinks you need to have installed. To flow central heating into the conversion, a Gas Safe registered engineer will be able to look at your boiler and suggest the most appropriate way to connect up radiators and any other appliances requiring heating or hot water.


How much does electrical work for a garage conversion cost?


The average cost of electrical work in a garage conversion is £550.

A certified electrician will be able to add sockets and complete any rewiring that’s required to deliver power and light into your newly converted space.

Typically, each new socket will cost £100, but you can usually negotiate a deal if multiple power points are required. Rewiring a room could cost as much as £1,000, but make sure you ask your electrician about the strain this may place on your mains supply. In some cases, a new circuit will need to be added for the garage.


How much do doors and windows for a garage conversion cost?


The average cost of a door or window for a garage conversion is £550.

To make your new space feel more like a room (and less like the place you once stored old car parts) you can install windows, as well as filling the space that was occupied by your garage door with a set of smart patio doors.

Your original garage structure probably won’t have featured much glazing, so installing UPVC windows or doors can really help to open up the space and provide plenty of natural light. That said, it’s also worth thinking about the desired layout of the room. Depending on where you’re planning to introduce furniture, wall space could be more desirable than doors or large windows.

Each window or door will cost £550 on average and you can expect to pay more for high-end options like bi-fold doors. It’s worth paying the extra for double-glazing, which will help to retain heat and contribute to the insulation of the conversion.

When choosing your windows and doors, keep the overall style of your home in mind. You’ll want the garage conversion to blend in seamlessly with the design of your home.


Appendix – Costs

Low Average High
Garage conversion costs
Single garage conversion (18 sqm) £16,245 £19,000 £22,700
Double garage conversion (36 sqm) £31,300 £37,000 £43,000
Miscellaneous costs
Garage doors – removal and installation of new weathertight door £1,000 £1,300 £2,000
Supply and fit external doors and windows £500 £550 £600
Supply and fit flooring £1,000 £1,300 £1,750
Install new gas and water pipes £1,000 £2,000 £3,000
Install new electrical sockets £75 £190 £430
Install stud wall (insulated) £700 £750 £800

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