Garage Gym Conversion: Costs, Process & Tips (2025)

If you want more living space, a garage conversion can be the way to go.

Not only do most homeowners not fully utilise their garages – converting a garage into living space costs as little as half as building a new extension. And, that’s without sacrificing prised garden space. 

At the same time, most conversions still cost from about £469 per square metre or between £469 and £1,200 per m2. That can go much higher, depending on the type of work you want done.

And, that means that a single garage conversion will cost from £7,500 but averaging £10,000 and a double garage conversion will cost from £14,000 but more likely up to £30,000. 

For example, for a 30 m2 garage conversion with large double glass windows and a sliding glass door, you can expect the following costs*:  

*Please note these cost estimates are based on quotes given at the time of writing in May of 2023. Actual rates are subject to change and may be different at the time of reading.

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Why Convert Your Garage To A Gym?

Garages are one of the most underutilised spaces in the home. Even if you have an auto, chances are, it’s too small to fill the space. That’s especially true if you have a double or very large single garage – which means you may have up to 30 square metres of space in your garage. 

Most of us fill that space with boxes, the odd tools, and things we’d otherwise throw away. Cleaning out that clutter can free up the space for social living, including things like a home gym.

Most importantly, if you have a big garage, you don’t even have to sacrifice your full garage. A partial garage conversion doesn’t cost much more than a full conversion, and you’ll keep enough room to part a single car. 

• Your auto still fits on the driveway.
• Home gyms make it more likely you’ll be able to work out.
• Dedicated fitness spaces can be part of socialising.
• You can knock out the wall between the living room and garage to expand your living room while you’re at it.
• If you already work out at home, giving yourself more space can feel like a luxury, while freeing up another room for a bedroom.

There are plenty of reasons you might want a gym at home. And, converting your garage means you can have that, more space for laundry or other necessities, and a wider living room, all in one go. 

How Much Does A Garage Gym Conversion Cost?

Converting your garage to a gym will cost anywhere from under £10,000 to over £30,000. Normally, costs depend on the size of the space, the extent of modifications, and what you’re paying in labour. 

Size of the Space

The larger your space, the more it will cost to convert. On average, you’ll pay £469-£1,200 per square metre. This means that if you want to convert a full double garage, costs will likely be double those of converting a single garage.

While you’ll typically pay slightly less for time and labour as you scale up, it shouldn’t be enough to really make a difference for your project. 

Material Costs

Materials are a considerable part of the cost of converting a garage to a gym. For example, if you want to replace the garage door with a wall, you’ll have to pay for those materials.

That works out to: 

• £66+ per m2 for brick
• £600-£1,200 per m2 for glazing 
• £60-£200 for concrete 
• £40-£150 for flooring
• £5-£25 for insulation 
• £450-£800 for radiators 

Eventually, however, there are no real upper limits to costs. You can always choose more expensive materials.

For example, if you want a traditional floor in your gym, you can go for cherry wood, at over £200 per square metre. It’s unlikely you’d want to do that, when you could have a standard hardwood for as little as £50 per square metre or laminate for as little as £12. But, you could. 

Figuring out which materials you want also means deciding on budget, figuring out how much you want to match the existing house, and making decisions around that. 

Amount of Glazing/Glass

Gyms are often the nicest when they are wide open and airy spaces. That normally means using a lot of glazing in the front and possibly the sides.

Here, you can always opt to knock out part of the side and back walls to install glass windows and doors. You can also opt for sliding glass doors or very large windows in the front. 

However, how much you do there should depend on what you want to do with the space and how visible it is from the street. And, if you normally have an auto parked there anyway, you might not care too much about having a good view of it. 

Still, glazing is costly. If you’re installing sliding glass doors, you’ll normally expect to pay about £1,500 for them but as much as £2,700.

In addition, you might want glass panes around those which will cost an average of £400-£800 each. On the other hand, if you want simple, traditional windows, prices start out at about £600. 

More glazing means more light and the appearance of more open space in your gym. It also makes the space a better socialising area if you end up using it to socialise and work out. 

Cost of Labour 

Most garage conversions can be primarily handled by a general contractor with some help from an electrician and some help from a plumber. Here, you’ll pay about £150 per day for general contract labour – or about £30 per hour if you’re not paying a day rate. 

In most cases, a garage to gym conversion will require at least two people. And, the project could take up to 6 weeks.

However, you might not be having people on-hand every day. For example, if you have to lay a mini foundation, you’ll have to wait for it to cure before the work resumes. 

So, you can assume that you’re paying £300 in labour costs for every day of the project. Your bricklayer may also charge a flat rate instead. That’s likely to be about £1,000 per day for 1,000 bricks, or roughly 8 square metres of double brick wall.

Of course, they could charge you for the materials and the labour separately. But, if you have a day rate – you’ll likely only need a single day of work to close off the front of your garage. 

Insulation 

You’ll have to insulate the floor, walls, and ceiling of your new gym if you’re connecting it to the central heating.

On average, you’ll be paying £5- £25 per square metre for insulation. Here, you can have either batting (fibreglass) or an insulation board. If you pay more, you can opt for fibrefill or other blow-in insulations. 

Insulation can be as low as £2.50 per square metre. It can also go over £55. In most cases, the £5-£10 options are more than enough for your garage. However, you may want to double-insulate the ceiling – but discussing that with your contractor is a good call. 

Heating and Electric 

Your electrician will normally cost that for the first hour of work. However, unless you need several new spurs to support high-electricity equipment for your gym, they won’t take more than an hour. 

On the other hand, if you want a home gym with a tanning bed and a sauna, you can expect to need a 20 amp spur. So, you might be looking at 4 hours of your electrician’s time. 

You’ll also want to install heating. That could be underfloor heating or radiators attached to the central heating. In either case, they’ll cost £400-£800 including labour, unless you opt for particularly fancy radiators.  

Building Project Timelines

It can take anywhere from 2-6 weeks to convert your garage into a gym. 

• Find a contractor.
• If you’re expanding the building, contact planning permission.
• Assess if you have to pour a foundation to build a front wall.
• Add a supporting frame or scaffolding to the front of the building.
• Remove the garage doors.
• Frame and pour the foundation for the new wall.
• Lay the brickwork for the new wall.
• Cut new doors and windows.
• Fit new doors and windows.
• Lay floor supports.
• Install any framing for insulation.
• Install insulation.
• Fit the subfloor.
• Run electrical wiring.
• If using underfloor heating, fit the underfloor heating.
• Add drywall.
• Plaster.
• Fit lights and other electronics.

Eventually, the project timeline will also depend on other factors that come up during the build, such as if the garage is in good enough shape. 

Do You Need Planning Permission?

It’s very unlikely that you’ll need planning permission to convert a garage into a gym. However, you may need planning permission if: 

• You’re installing a separate toilet and shower 
• The building can function as a standalone home 
• You’re expanding the room beyond its existing walls 
• The design adds a storey to your garage 
• You live in a listed building 
• There’s a clause in your buyer’s contract that limits building on the property 

Otherwise, you shouldn’t need planning permission. If you meet any of the above-listed requirements, contact planning permission. The fee for an application is £60. However, you’ll normally end up spending another £200 on administrative fees as well. 

What About Building Regulation?

You’ll always have to notify building control of any major modifications to your home. This includes for: 

• New radiators
• Changing electrical outlets
• Adding insulation 
• New windows
• Adding a door 

Chances are, you’re doing all of those as part of your conversion project. However, you’ll be able to submit a single notification for the full project.

In addition, if your builder is part of the Competent Person Register, they can self-inspect and self-notify, meaning you won’t spend extra on safety inspections for wiring, heating, and walls. 

In either case, the fee for notifying council changes based on location. Here, it’s always between £170- £690, with £170 being the standard cost. However, you’ll have to check your local council fees to see what it costs in your area. 

Builder Hiring Checklist

If you’re hiring a builder to do a garage conversion for you, you want to ensure that they are qualified, well-reviewed, and capable of doing a good job. 

• Can provide a detailed quote that compares favourably with competitors 
• Take ownership of waste and leftover materials
• Are available during the timelines you’d like
• Are part of the Competent Person’s Register
• Will notify council for you 
• Have liability insurance
• Offer a workmanship guarantee
• Include worker’s compensation 
• Subcontract out work they can’t complete themselves 
• Have good reviews and references 

You can also look into checking what the builder has worked on in the past. And, if you like a builder but not their quote, you may want to try to negotiate. However, it’s unlikely to get you very far, as most use flat and firm rates. 

8 Benefits of Having A Gym At Home

There are plenty of reasons to have a gym at home, although if you’re taking the plunge, you probably want to already be quite accustomed to working out regularly. 

1. It’s easier to go to the gym because you don’t have to commute.
2. You save time (e.g. no packing bags, bringing food, packing stuff for a shower, driving/walking, etc.).
3. More freedom to choose when to workout.
4. No gym membership fees.
5. More space to workout than in a loft or small spare bedroom.
6. Family can join in.
7. You won’t have to pay for childcare.
8. Completely customizable gym equipment.

Having a gym at home also doesn’t mean you have to give up on going to the gym as a social activity. You can just invite your friends over. 

Does Converting A Garage Add Value?

It’s unlikely that converting a garage to a gym will add value to your home. That’s especially true if the next owners would rather have a garage to park their cars.

However, a converted space can be re-used for a living room area or even a bedroom depending on what people want. This means you’ll be able to market the home as having more living area – not just a gym. 

In addition, if you have a large double garage, you can convert it to a gym without losing all of your garage, and you can move the house to market with both extra living space and a garage. 

On the other hand, if you just want a mortgage, that mortgage may be offered based on habitable living space and not on garages and other extras, so it may increase the amount you can borrow on your home. 

Next Steps

If you’re ready to convert your garage to a gym, it’s a good idea to get started by figuring out what you want. Deciding on how much glass you want, materials, and even flooring upfront will give you insight into what your contractor should specialise in and what your budget should be. Once you have that down, you can start requesting quotes and compare them to find the best contractor. 

If you’re ready to get started, use the form at the top of the page to request quotes from local contractors.