Garage conversion are a versatile solution for homeowners looking to maximise living space and add value to their property. From creating an additional bedroom to a home office or gym, converting a garage can transform underutilised space into a functional living area.

However, garage conversions can be costly, so it’s important to plan and budget effectively. Let's explore how much a garage conversion costs and what you need to consider before you go ahead.

How much does a garage conversion cost?

Garage conversion costs in the UK typically range from £10,000 to £25,000 or more, depending on the size, complexity, materials, and location of your garage conversion. The average cost for a basic single garage conversion is around £10,000 to £15,000, while larger or more complex conversions can exceed £20,000.

Single integral garage	£12,000
Single attached garage	£15,000
Detached garage	£20,000
Double integral garage	£25,000
Double detached garage	£33,000

These costs are averages taken from across the UK. If you live in London or the south east, you may pay more than these averages, while in more rural areas and the north of the UK, you may pay less. Take a look at our rates for garage conversions across the country in our table further down the page.

What affects the cost of a garage conversion?

Several factors can influence the cost of a garage conversion:

• Size and complexity: The bigger your garage is, the longer it will take to convert. And if you have a complex design that requires adding extra plumbing for bathrooms or kitchen areas or you need stud walls, this will increase the cost too.

• Quality of materials and finishes: As you’d expect, premium materials and finishes will drive up the cost. Consider your budget; some materials, like luxury tiles and hardwood flooring, may be worth spending extra money on, while you might decide that light fixtures or furnishings are worth saving on.

• Structural alterations: If your garage needs structural reinforcement before it’s safe to be used as an additional room in your home, you’ll pay more in material and labour costs. This isn’t something you can try to cut corners on – to meet building regulations and ensure your garage conversion is safe, you must ensure your extension builders carry out all the required structural work.

• Planning permission: Many garage conversions will come under permitted development, meaning you won’t have to apply for planning permission. However, if you live in a conservation area or you want to make changes to the exterior of your property, you may need to apply. A straightforward planning application usually costs £322. If you’re unsure whether you need planning permission, it’s always best to check with your local building control.

• Where you live: Where you live has one of the biggest impacts on the cost of your garage conversion. The cost of living varies across the UK, so labour prices differ accordingly. You’ll pay more if you live in the south east or London, while northern areas typically pay less.

What is the cheapest way to convert a garage to a living space?

Converting a garage into a living without altering its structure is generally the most cost-effective option. Opting for basic finishes and only utilising existing utilities, such as electricity and plumbing, will also help keep costs down.

It’s also cheapest to simply change your garage door to one with a window rather than bricking up the opening and adding a proper double glazed window. However, you’ll add more value to your home if you spend the extra money on bricking up the old garage door space.

How long will a garage conversion take?

How long a garage conversion takes depends on the type and size of garage you have and the complexity of the design. On average, a garage conversion will take 2 to 4 weeks to complete, while larger conversions with extra pipework or electrics required may take 6 to 8 weeks or longer.

Do I need an architect to convert my garage?

While it's not a legal requirement to hire an architect for a garage conversion, their expertise can be valuable in ensuring your garage conversion design meets building regulations and maximises space effectively. Architects can also provide guidance on structural alterations, planning permission and compliance with regulations, reducing the risk of costly mistakes.

Do you need planning permission to convert a garage to a room?

In many cases, garage conversions fall under permitted development rights and may not require planning permission. However, if you plan on making significant changes to the external appearance of your property or if you will enlarge your home, planning permission may be required.

If you want to convert your detached garage into a separate house, regardless of who will live in it, then you will need to apply for planning permission.

It’s always best to check with your local planning authority before you start work, especially if you live in a conservation area or on a new housing development, as sometimes permitted development rights are removed from these properties.

Do you need building regulations approval for a garage conversion?

Yes, building regulations approval is always required for garage conversions to ensure compliance with safety, structural and energy efficiency standards. Building regulations cover aspects such as insulation, ventilation, fire safety and structural stability, and you must get sign off from your local authority when the conversion is complete. If the work to your garage isn’t up to standard, you won’t be able to use it as a ‘habitable’ room, which will affect the value of your home.

Does converting a garage devalue your house?

There isn’t a straightforward answer to whether converting a garage devalues your house. If the conversion is poorly executed, it could reduce the property's overall appeal to potential buyers. However, a well-designed and properly constructed garage conversion that adds usable living space and enhances functionality is likely to increase the value of your property.

Usually, if you convert your garage into an additional bedroom or a home office, you’ll increase the value as these features will appeal to buyers. But some buyers will want to have a garage no matter what, so you may find you reduce your pool of buyers if you come to sell your property.

Do you need foundations to brick up a garage door?

Yes, you do need foundations to brick up a garage door. If your garage’s foundations don’t continue underneath the garage door opening, or there’s no concrete slab to support a brick wall, you’ll need to dig foundations.

Your builder will need to dig at least a 1m footing or to the same depth as the foundations of your garage and then fill it with concrete. If there’s an existing concrete slab present, it needs to be at least 200mm thick. Instead of footings, your builder may recommend adding concrete lintels to each side of the opening below ground level.

What is the 4-year rule for garage conversions?

The 4-year rule refers to a provision in planning law that allows certain development, including garage conversions, to be considered for retrospective planning permission up to 4 years after they’ve been built. You can apply for a Certificate of Lawfulness to prevent your local authority from sending you an enforcement notice.

However, this rule is due to be updated to a 10-year rule at any moment, as part of the Levelling-up and Regeneration Act that was passed in October 2023.

Rather than relying on the 4- or 10-year rule, it’s always best to ensure that you apply for planning permission when required and ensure all work meet building regulations.

Can a converted garage count as a bedroom?

Yes, a converted garage can count as a bedroom as long as the conversion meets all the relevant building regulations regarding adequate size, ventilation, natural light, fireproofing and escape routes. You’ll also usually need to fill out a ‘change of use’ form.

How difficult is it to convert a garage?

It doesn’t have to be difficult to convert a garage, but it depends on what you’re planning to use it for. If you’re happy to simply change the garage door to one with a window and put temporary fixtures and fittings down to change it into a living space, this can be relatively easy for an experienced DIYer. If you don’t make drastic structural changes you can avoid needing to fill out a ‘change of use’ form and change it back into a garage when you come to sell the property.

However, if you want to convert your garage into a permanent extra living space or bedroom, this is much more difficult. You’ll need to ensure you comply with building regulations and make sure the conversion is safe to use as a permanent living space, so we’d always recommend using a qualified and experienced builder.

Is it worth converting my garage?

Only you can decide whether it’s worth converting your garage. While you’ll add valuable living space, improve your quality of life and potentially increase the value of your home, there’s also considerations like cost, planning requirements and potential impact on resale value to take into account.

Make sure you consult with professionals such as builders, surveyors, architects and structural engineers before making your final decision to ensure you’re making the best one for your property and your family’s needs.

Post a job on HaMuch now to get in touch with extension builders in your area who can advise on whether a garage conversion is the right option for you.

Estimates for common extension builder jobs;

Rates for other trades