Garage conversion costs: draw up a budget with our complete guide

Need to know about garage conversion costs? Find out how much you can expect to pay to gain extra space

Garage conversion by OB Architecture
(Image credit: Martin Gardner)

If you’re planning to extend your home by making use of the space the garage offers, garage conversion costs will be a major part of your considerations. 

A garage conversion can seem like a relatively straightforward way to gain additional square meterage – and without having to sacrifice precious garden space to do so. But knowing what you need to budget for, and how much you might expect to pay, is crucial in deciding if this is the right project for your home.

We’ve put together a guide to all the factors that can influence garage conversion costs along with their price tags here, and asked the experts to share their know-how, too.

Garage conversion costs

Garage conversion costs depend on your project, but what it will set you back will usually be lower than the costs associated with a house extension

However, the cost of a garage conversion varies widely. ‘Prices for garage conversions range from £469 to £1,200 per square metre,’ says Thomas Goodman, property and construction expert at MyJobQuote (opens in new tab)

Costs will be influenced by both the garage size and type. ‘Costs for an integral garage conversion range from £7,500 to £12,600,’ says Thomas. ‘The cost to convert an attached garage ranges from £10,000 to £20,000. Costs for converting a detached garage range from £15,000 to £25,000, and a double garage conversion cost (based on 36 square metres) is £17,500 for an integral or £45,000 for a detached garage conversion.’

The type of space you want to create within your home also bears on the cost. ‘For example, remodelling your garage into a kitchen or bathroom is significantly more expensive than a living room or bedroom,’ explains Thomas.

If you just want to turn your garage into a space such as a gym or an upgraded storage space, you could consider a modular system, such as that from Garageflex (opens in new tab), which permits just one wall, the ceiling, or the floor to be done at a time for a partial conversion, or a full conversion in smaller stages.

For an accurate estimate of how much your garage conversion project will cost, use our extension cost calculator.

Dining area in a garage conversion with floor to ceiling windows

(Image credit: ZaZu Designs)

Garage conversion design costs

You don’t have to employ an architect to design your garage conversion, but if you decide to, factor in the costs. Expect to pay an architect for design fees at around three to seven per cent of the build cost. Meanwhile, architect garage conversion drawings cost around £2,000, according to Checkatrade (opens in new tab).

You might need a structural engineer, too, to provide professional advice on foundations and other aspects of the conversion. ‘A structural engineer may cost as little as £200 for an initial consultation,’ says Thomas Goodman. ‘The typical hourly rate would be between £50 to £100.’

Factors that might affect garage conversion costs

There are a whole host of factors that can affect garage conversion costs. 

Soundness of the structure

Typically, a garage conversion will cost more if the original structure is unsound. If you are going to spend a lot of money stabilising the building, knocking the original garage down and building from scratch might actually be cheaper.

Location

Also important in some cases is the distance between the garage and the house. ‘A garage further from the main house might require a separate power source or plumbing and trench digging for supply connections,’ says Thomas Goodman.

Door replacement

The garage door will have to be replaced with a new wall and/or window. Expect to pay around £1,600 for replacing a door with windows.

Labour costs

Labour costs for the conversion will depend on what you have decided to use the additional space of the garage for. ‘For example, expect to pay a plumber between £170 and £220, a kitchen fitter between £130 and £160, and a joiner between £150 and £200,’ says Thomas Goodman.

Note that these are daily rates, with most trades needed for one to two days for a garage conversion project.

Be aware that these costs might be included in what you’re quoted, depending on who undertakes the work. ‘Most contractors will provide a quote for the entire project; some experts will include all the work, including structural engineers and the necessary paperwork, in the price,’ says Thomas.

Partial conversion

A partial conversion should cost less, but not by much. Fewer materials will be needed, but services, such as electrics and plumbing, will still have to be installed and budgeted for.

Cost of garage conversion interior fit-outs

Garage conversion costs need to incorporate the interior fit-out – the cost of which really does depend on exactly how you'll be using the room. However, you can use the figures below as a rough guide. If the room is to be just an extra living space, perhaps as a playroom, make sure you futureproof the wiring and lighting in case you want to convert it into a TV room in years to come.

An internal structure of stud walls built inside your garage will have insulation added to increase energy efficiency. Expect to pay from around £750 per stud wall.

  • To add a kitchen in a garage conversion, budget from around £5,000 to £20,000, depending on the specification; if you go high end, costs can increase significantly.
  • For a bathroom, factor in from around £4,500 to £11,000 for the plumbing and fittings.
  • For a shower room, utility or boot room, perhaps with a big sink for washing dogs, plan for between £4,500 and £11,000.
  • For flooring, budget in the region of £25 to £100 per square metre.
  • Expect to pay around £100 to have a new electrical socket fitted; this price will be negotiable the more electrical work you are having done.

a conversion of a integral garage

(Image credit: Berry Construction)

Adding heating

Your plumber may be able to extend your existing central heating system, which will mean a couple of day's work, at around £170 per day, excluding materials. 

If you are opting for underfloor heating in this room only, electric underfloor heating will be a less expensive option to install (a DIYer can fix it in place, but it needs to be connected to the mains by a qualified electrician; day rates are around £220 per day). If your garage conversion is part of a larger renovation, water-fed underfloor heating will be cheaper to run over time, if more expensive to install initially. 

You may need a new boiler to meet the underfloor heating's demand; the Energy Saving Trust (opens in new tab) estimates the cost of a gas boiler replacement at around £4,000.

Planning permission fees

It's likely you can convert a garage under permitted development rights. If you can, as a safeguard for the future, it's worth applying for a certificate of lawful development from your local authority in any case, at a cost of £103 in England. ‘This is an important document to have if you decide to sell your house,’ says Clive Holland, broadcaster on Fix Radio (opens in new tab), a station for tradespeople and builders.

If you do need to apply for full planning permission, this costs £206 in England. Listed properties will need listed building consent, too.

Building regulation fees

A garage conversion requires building regulations approval. You can use the council’s building control service or an approved independent inspector, costing around £300. For details, check out the government’s planning portal.

Party wall agreement fees

If the work affects a structure shared with an adjoining property, the party wall act will also apply. Expect to pay up to £1,000 for a party wall agreement with your neighbours – although if you are able to persuade them to sign a waiver, you'll save yourself this cost.

How to save on a garage conversion

There are ways to make a garage conversion a less costly project. 

‘Clear the existing garage of clutter, furniture, and worn-out flooring to help your contractor finish the job faster,’ advises Thomas Goodman. ‘If you’re able to move things before they enter your property, it can ultimately save time and money compared to paying them to do the heavy work for you.’

You might also want to take on the decorating yourself at the end of the process. ‘You will avoid paying painters and decorators a few hundred pounds per day,’ says Thomas.

Planning ahead can also bring savings. ‘Take advantage of sales or discounted rates in trade shops before your project when planning your conversion,’ says Thomas. ‘By doing this, you can afford a little more premium options because they aren’t at their RRP, which will help lower the overall costs and give you more freedom in your choices rather than forcing you to go the most inexpensive route.’

How much does it cost to convert a garage into a room in the UK?

Final garage conversion costs depend on a number of factors. However, it typically costs between £9,500 and £20,000, with an average cost of £14,500, according to Checkatrade.

Thomas Goodman of MyJobQuote advises that you should expect to pay the following average cost per square metre, with the average high-end prices also listed, based primarily on location, as the average cost for a garage conversion along with materials and labour: 

  • Average-sized integral garage £400 to £700 per square metre 
  • Average-sized attached garage £750 to £1,000 per square metre
  • Average-sized detached garage £1,000 to £1,600 per square metre

How much does it cost to turn a garage door into a wall?

The cost to turn a garage door into a wall is influenced by how much work is required. 

‘To build a wall and add a window, you'll need to consider the cost of the materials and the cost of hiring the various contractors,’ explains Thomas Goodman. ‘Sometimes, a small foundation may even be required; a structural engineer can advise you. The price range for removing garage doors and bricking a wall is between £1,600 and £2,200.’

How much does it cost to convert a 2-car garage?

The cost to convert a two-car garage is affected by whether the garage is integral, attached or detached, and the quality of the conversion. 

‘You can anticipate spending between £6,000 and £11,000 for a low cost conversion and between £10,000 and £14,000 for a mid-range version for a two-car integral garage,’ says Thomas Goodman. ‘A budget option for an attached double garage will run you between £12,000 and £18,000, while a mid-range option will cost you between £15,000 and £25,000.

‘Budget detached double garages cost between £30,000 and £40,000, while mid-range detached double garages cost between £40,000 and £50,000.’

Lucy Searle
Lucy Searle

Lucy is Global Editor-in-Chief of Homes & Gardens having worked on numerous interiors and property titles. She was founding Editor of Channel 4’s 4Homes magazine, was Associate Editor at Ideal Home, before becoming Editor-in-Chief of Realhomes.com in 2018 then moving to Homes & Gardens in 2021. She has also written for Huffington Post, AOL, UKTV, MSN, House Beautiful, Good Homes, and many women’s titles. Find her writing about everything from buying and selling property, self build, DIY, design and consumer issues to gardening.

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