Garage Conversion UK

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Garage conversion UK

Whilst a garage is supposed to be a handy place to store our cars on an evening, a recent study by RAC Home Insurance found that four in ten of us can no longer fit our car into our garages due to the amount of clutter we keep in them. 

If this is the case for you, then you may be thinking about converting your garage into a multifunctional room. Not only will this give you more storage space within your home, but it can also add value to your property. Virgin Money estimates that converting a garage into an ensuite can add 20% to the value of your home. 

As an average estimate, your typical garage conversion can cost around £6,000, so it can be a very cost-effective way of both increasing living space as well as investing in your home. 

If you are wondering whether a garage conversion is the right choice for you, then read on. In this blog, we will be looking at everything you need to know about garage conversion UK. 

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How much does a garage conversion cost? 

If you are considering a garage conversion project, then the first thing you will want to know is how much it is likely to cost you. The good news is that a garage conversion is a relatively inexpensive project as far as home renovations go. This is due to the fact that unlike with an extension, you will not need to fork out for the laying of new foundations or building new walls. Another factor keeping the cost lower than other home renovation projects is the chances are your garage is already connected to the power lines. 

This means the average cost of carrying out a garage conversion is anywhere between £5,000 and £7,000. However, this figure is only a ballpark estimate and is subject to change if plumbing is needed or if there are structural changes. 

What other factors can affect the cost of my conversion? 

Other factors at play that can have a knock-on effect on the cost of your garage conversion include: 

  • If you use an architect or a designer 
  • Planning applications 
  • Whether you use a structural engineer
  • If the ceiling height needs to be raised
  • If there are any walls or floors in need of replacement 
  • Whether or not the foundations need to be reinforced

How long will a garage conversion take? 

Once you get the building work underway, a garage conversion can be pretty quick. Depending on the condition and structure of your garage, it can take as little as 3-4 weeks to complete. On average though you can expect for it to take between 3-6 weeks.  

Is my garage suitable for conversion? 

Now we have an idea of how much a garage conversion can cost, you may be wondering if your garage is suitable for conversion. Whilst every garage is different in size, as an average you can expect the following from your garage conversion: 

  • Single garage – If you convert your single garage, you can expect to add an average of 150 sq ft to your home. 
  • Internal single garage– This is the easiest type of garage to convert as it is built into the structure of the home. This will also typically add around 150 sq ft to your property. 
  • Double garage– Double garages are well suited for splitting the area into two, whether that’s a living room and a kitchen or any combination you want. They will typically add around 300 sq ft to your property. 
  • Standalone garage – If you have a standalone garage, then you will be able to add 150 sq ft with a garage conversion. However, as it is a standalone structure, you will need to be wary when it comes to planning permission. 

Why do people get a garage conversion? 

There are many different reasons why you may be considering a garage conversion for your home. Below are some of the most popular uses for garage conversions: 

  • Home gym 
  • Home office 
  • Extra bedroom 
  • En-suite 
  • Home cinema 
  • Utility room 
  • Larger kitchen 
  • Children’s playroom
  • Lounge 

Do I need planning permission to convert a garage?  

When it comes to garage conversions, the majority can be completed under permitted development rights, especially if your conversion does not require alterations to the main structure of the building. However, it is always a good idea to make sure that there are no planning permissions attached to the garage. For example, a common clause is that they have to remain as parking. You can do this by checking the deeds of the property for any permissions. 

If you are converting a detached garage, then it is worth bearing in mind that you may have to apply for a change of use. It is often worth checking with your local planning authority to make sure that your garage conversion falls within the permitted development. 

In the event that you own a listed building or are in a conservation area then the chances are you will need to require planning permission before you can begin your garage conversion UK. 

What building regulations does a garage conversion need? 

As with any ‘change of use’ conversion or renovation, a garage conversion will require building regulations approval. This means that your garage conversion must meet the following criteria in order to comply: 

  • Have a damp-proof course 
  • Be energy efficient e.g. wall, floor, and loft insulation 
  • Have good ventilation with moisture-proofing 
  • All electrical goods should be safety tested 
  • Be fire-proofed and have escape routes planned 
  • The garage is structurally sound

It is important that you notify your local council before you begin work as you will require building regulations. Depending on whether or not you will require planning permission or not, you can do this in two ways, by either submitting a full plans application or a building notice. 

When you finish converting the garage, a building inspector will issue a certificate of completion once they have checked doors, windows, garage foundations, and fireproofing measures.  

Main stages of a garage conversion project

Converting a garage into extra space for your home means different things for every homeowner. Some wish to use their new space for a  home office, while some wish to use the new habitable space as an extra bedroom or bathroom. Whatever your motivations, there are several main stages of a garage conversion which remain the same regardless if your aim is extra living space or an ensuite. 

Floor slab

The first step of many garage conversions is to look at the foundations and floor and see if they are in need of an upgrade. This is an especially important stage if you are looking to add new windows or doors to the structure. 

The best way that you can test to see if your foundations are up to the task is by digging trail pits. If the garage foundations are at least 200mm deep, then they should be able to withstand the conversion. If this is not the case, or your structural engineer says otherwise, then you may need to look at getting additional support for your conversion. 

On top of this, the existing garage floor may require work done to it such as levelling, damp proofing and insulating. 


Rather than keep the existing garage door, a lot of building conversions will simply brick it up and cover it with walling that matches the rest of the property. This will typically be a masonry infill, which is fully toothed and bonded into existing brickwork. 

Garage wall insulation 

You may find that if you have an integrated garage that has been built to a similar standard as the main house so your walls may already have been insulated. If not, you will be able to insulate them internally. This can be done by simply erecting studwork on the inside of the walls, then using timber deep enough to accept sufficient insulation, and then all that’s left to do is to plasterboard over the top. 

Roof insulation 

The most effective method of insulating the loft is using a pitched covering at loft level. Another way you can insulate your garage roof is with a warm roof set-up. This involves insulating the roof at the rafter level. 

If your garage has a flat roof then it will need to be fitted with rigid insulation both under and between the ceiling joints. But you must leave a ventilation gap above in order to prevent condensation. 

Adding new windows and doors 

It is important to keep in mind the style and the structure of your garage when choosing new doors and windows to be fitted. In terms of specifications for your windows and doors, building regulations require a minimum U-value of 1.4W/m2K. The windows will need to provide ventilation, as well as a potential fire escape route depending on the layout of your conversion.

Heating and electrics

Chances are, you are going to need new heating loops and electrical circuits fitted into your garage conversion. This will put added strain on your boiler, so you may need to upgrade your system, which will add money to the conversion. 

Can I do a DIY garage conversion?

Yes, you can! A DIY garage conversion can be a great option if you have a small budget and are competent with DIY.  However, you should only consider this option if you are confident completing DIY tasks, as once the conversion is complete, the project will need to be checked by a building control officer and if it does not comply with regulations, the expense to fix it will come directly out of your own pocket. 

Can I design my own garage conversion? 

When it comes to deciding how your garage conversion will look, you are spoilt for choice. One option is designing the conversion yourself, however, if you are not confident doing this, there are other options. You could hire an architect or an architectural designer or alternatively, you can simply use a builder or a building company that specialises in garage conversions. 

Garage conversion insulation requirements

Insulating your garage conversion is an important step in your garage conversion. Your new room will need to be insulated correctly to ensure that it is warm and energy-efficient. 

The easiest way that you can insulate your garage walls is by adding insulated plasterboard that is fitted with timber battens above the damp-proof course.

Luckily, garage floors are often a lot lower than the rest of the floors on your property. This means they can be insulated easily with a damp-proof membrane, insulation, and a new screed plus floor covering.  

What insurance will you need for an average garage conversion?  

If you decide to hire a builder to build your garage conversion, they should bring their own insurance to cover the project. Before they start to work on your home you should always check to make sure that they have indemnity insurance before they start work. 

You should also inform your home insurance provider before you start your conversion project. Major building works have been known to invalidate home insurance, so it is in your best interest to check before you move ahead with the conversion. In the event that your home insurance provider will not cover you, you will need to take out specialist additional insurance. 

After the work has been completed, you should reach out to your home insurance provider again as the work may have increased your rebuild value. If this is the case then your premiums may rise. 

Converting a detached garage

If your property has a detached garage then you may be facing a bigger job than converting an integral garage. The first step is to apply for a change of use with your local planning authority. 

When budgeting your conversion, you will also need to factor in extra costs such as enhancing the foundations, which may not be strong enough. You will also need to factor in the cots for adding plumbing and power to the garage. 

Advantages and disadvantages of a garage conversion UK  

As with any home improvement, there is plenty to consider when it comes to garage conversions. Below we take a quick look at the advantages and disadvantages of converting your garage into a liveable room…


  •  Fairly cheap to construct 
  • More living space 
  • Adds value 
  • Relatively quick to finish 


  •  Potential to affect council tax  
  • Planning permission  
  • Lose some storage space (as whatever you are storing in the garage will need to be rehomed)  

Should I convert my garage?

Whether or not you should convert your garage into a liveable space is completely up to you. A converted garage is not only a great way to add space to your home but it also adds value to your home. They are relatively cheap in the grand scheme of conversions and renovations as well as being fairly quick to complete. 

However, there are also downsides to the conversion that you will need to consider. It has the potential to increase your council tax, as well as complications with planning permissions and losing storage space to the items you were previously keeping in your garage. 

As is the case with any conversion or renovation, it is always wise to do your homework and carefully research the process, pros, cons, and cost. 

That covers everything you need to know about garage conversion UK. If you have any insight or queries into the matter, please feel free to get in touch

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photo of Alexandra Ventress

Alexandra is a junior content producer who enjoys writing articles and finding out more about the property market. Read more about Alexandra here.

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About Alexandra Ventress 91 Articles
Alexandra is a junior content producer who enjoys writing articles and finding out more about the property market. Read more about Alexandra here.

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