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How much does a garage conversion cost?

Many homeowners turn to the garage conversion as a cost effective option for adding new space - but how much are they really? Find out...

6 min read

If you are looking to create some space at home and are happy to part with your garage, then a garage conversion might be the ideal project for you.

Unlike extension alternatives, the garage conversion does not take up any valuable outside space as it only changes the existing structure. Their price tags can also seem very attractive when compared with other space-creating options...

How much does a garage conversion cost?

On average, when it comes to converting your garage, you can expect to pay:

Single garage (15m2): £6,000 - £15,000
Double garage (30m2): £12,000 - £30,000

However, like most home projects, each garage conversion is unique with costs dependent on your existing layout and project ideas. So here are just a few things you’ll need to consider beforehand…

Is a garage conversion right for you?

The first thing you should do, before parting with any of your cash, is to properly assess whether or not this is the right way to expand your home.


Garage conversions have loads of benefits:

  • They are easier on the old bank account as they won’t require too much (or any) building work. Instead the work will change-up the existing structure.
  • They won’t take up any of your lovely garden space, unlike a rear extension.
  • Planning is typically easier to obtain, due to works taking place inside an existing structure. In some cases, planning permission can be avoided all together with the use of your permitted development rights.

Learn about your permitted development rights in 2020.


Garage conversions have few downsides, except:

They come at the expense of your garage (duh).

Depending on where you live, this could be an issue. Whether or not you have a car, if parking is at a premium in your street, losing your garage could devalue your home.

What will you use it for?

When deciding if a garage conversion is right for you, you’ll also need to consider what room you plan on converting the space into. You could go for…

  • Kitchen extension
  • New bathroom
  • New bedroom
  • Home office
  • Home gym
  • Home cinema

The sky’s the limit!

But not all of these rooms are created equal. If you make any changes to the garage that limit the home for a future buyer (such as removing windows for that perfect cinema experience), then the value may be affected.

Typically, ground floor bedrooms and bathrooms will also bring in less value than their upstairs counterparts - just something to bear in mind if you plan on selling in the future.

Home office - garage conversion

Garage conversions: cost breakdown

Removing Garage Doors £1300 - £2000

Replacing your car hole with bricks and mortar is the most obvious job. To get a wall built, and window added, you’re going to have to factor in not only materials but hiring contractors too. You may even need a small foundation inserted, which a structural engineer can advise on.

New Doors and Windows £600 - £1500

To make your new room feel light and bright, you’ll probably want more than one window, and you might want to do up the access point. The price of these can fluctuate wildly, depending on whether you go for standard or bespoke.

Flooring £1000 - £1300

Most garages aren’t know for their nice floors, and in older properties, it can be particularly uneven. In order to make it fit for habitation, you’ll need to pour fresh concrete down before you can even think about carpets or hardwood floors.

Insulation £750 - £1000

In order to insulate your new room, and stop your heating bills from going wild, you’ll have to build stud walls inside your old garage. This allows for your roof, and the space between the old walls and new to be filled with insulating materials. There are many ways to insulate your home, all with different price tags, so research which one will be right for you.

Removing a wall £300 - £1200

If you’re opting to use your garage to expand your kitchen or dining area, you’ll have to remove the wall separating them. As you can see, the pricing can vary massively, depending on whether the wall you’re attempting to remove is a load bearing one - a structural engineer will be best placed to advise on this.

Utilities £1000 - £4000

If converting into either a bedroom or recreational space, you won’t have to do much in way of utilities. Most garages come with electrical wiring. However, if you’re converting into a bathroom, or working with a detached garage, that’s when costs can mount. You’ll have to install piping for water and gas, and the further your garage is from the main building, the more the price will increase.

Admin Costs £400 - £600

As most garage conversions happen within the existing structure, rather than actually expanding anything, you’re likely not to need planning permission. Instead, you should be covered by permitted development rights. You’ll still need to get approval from the council (which comes with a fee), and there could be more admin costs if the council doesn’t approve the work, or you need to arrange a party wall agreement with a neighbour.

Architect £700 - £2500

You might not need an architect for basic conversions, but if you’re looking to combine rooms, or design an annex, then getting an architect on board can help maximise your project’s potential. What’s more, they take care of the planning, making sure your admin costs don’t suffer from bad paperwork.

Building Regulations Application £500-1000

Building regulations are a set of standards that all properties must meet, based around design, construction, and alterations. Half of what you’ll pay will be for the application, and the other half for inspection costs. Prices will vary based on the scale of the work.

At Resi, we can take care of your design, planning and building regulations in one handy package. Book to speak with our team.

Factors that can affect your budget...

While we've tried to give you a rough idea on the average costs you'll face, there are some factors that can dramatically affect your budget.

  • The size of your conversion, the more square feet, the more budget you'll need
  • Where you live in the UK (London professionals charge a premium)
  • Your property type - listed buildings cost more
  • Whether or not specialist knowledge is required, such as timbre work
  • The amount of glazing you want to install
  • Quality of materials used
  • Quality of professionals involved

Want to know how much your conversion might cost? Book a free consultation with our team. We'll review your home and give budget estimates for your possible conversion options.


  • When deciding if a garage conversion is right for you, first consider whether you can afford to give up your garage. Where will you park? How will it affect the property value?

  • You need to know what you want to achieve before gauging the scope of your project. Will you need plumbing in your garage? How much glazing?

  • You will also need to consider which professionals are needed. Will you need plumbers? Structural engineers? Bringing an architect into the mix early can help you form your ideas and fully realise the space.

At Resi, our unique service offers design, planning, building regulations, finance and professional connect services all under one roof. Book a free consultation with our team for professional and affordable support on your happy home journey.

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