The Cost of a Garage Conversion

All you need to know about converting a garage including costs of materials, labour and time frames.

Cost of a Garage Conversion

What the job entails

Converting an existing garage is a cost-effective way to add some valuable Living Space to your home. Garage conversions can seem like a very attractive option in terms of costs when compared to the high costs of moving and the continually rising house prices. There are many ways to extend your home and garage conversions are perhaps the cheapest way, so if you don't already really use your garage space and treat it more as a junk room, then a garage conversion could well be the best option to free up some valuable space. If you have a double garage you could even just convert half the space so you still have somewhere to park a car while benefiting from an additional living room. One of the reasons that a garage conversion is so cost-effective when compared to a traditional extension, is that you don't need to lay new foundations or build new walls, plus many garages will already have electricity further reducing the overall costs of conversion. In addition to the extra living space, a garage conversion can add value to your property too!

Even though the building costs for a garage conversion are minimal when compared to building an extension, there are still some major alterations that have to be made. The first thing to consider with a garage conversion is the removal of the existing garage door which often simply needs blocking up with perhaps the addition of a small window. To convert a garage into comfortable living space doors and windows are essential, the number and size of the windows will determine the total cost, but typically a single door or window would cost in the region of £500 for a standard unit. With most garages, the existing floors are typically rough and uneven. So whatever type of flooring you require, you will usually have to pour some new concrete as a base. For the walls, stud walls can be built inside your garage to create a new room with insulation added between the stud walls and the existing structure. If you're changing your garage into a bedroom or living room and you already have electricity, then all you require is a few extra outlets. However, if you're turning your garage into a bathroom or kitchen, then plumbing and gas pipes will probably need to be installed. Once the basic structure of the new room is in place then it will, of course, require decorating and new flooring.

Converting a garage to a living space can help homeowners to make use of space that is not efficiently used. It is also not an especially complex project so many are tempted to tackle this as a DIY job to save money. But while a garage conversion is more straightforward than a typical extension project, there are still many important points to consider, such as insulation, ventilation and fire escape routes - all of which will need to comply with your local building control office under building regulations. In addition, the foundations will need to be checked to ensure that they can cope with the additional structure while both new and existing floors will require a suitable damp proof membrane. There is a lot to think about and approvals will need to be sought before any work starts. Any new electrical work carried out will also require an electrician. So a garage conversion is not a suitable job for first time DIY enthusiasts as it is a bigger project than it first appears!

Although a well-thought-out professional garage conversion can add value to your property (as much as 10%) making it one of the most cost-effective home improvement projects, a DIY bodge conversion job will reduce your property value and make the home difficult to sell! Don't be tempted to cut corners in terms of insulation either as this will cause condensation and damp which is not only a health hazard but will also stain and damage the new stud walls which will ultimately mean it will cost you a lot more in the long run. As with all home improvement projects, cutting corners and trying to do things on the cheap often will end up costing you more money.

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The Cost of a Garage Conversion

To provide accurate pricing information we got in touch with dozens of small and large businesses as well a few online quotation tools. Please remember that costs can vary greatly in different parts of the UK, and sometimes even small differences in specifications can cause prices to fluctuate significantly. Before hiring a garage specialist, we always recommend getting up to 3 quotes from local tradesmen in order to compare prices.

The average material cost to convert your garage will depend on the quality of materials you would like to use, the size of your garage, and exactly what you're converting your garage into. Materials will include those for flooring, insulation, heating, lighting, decorating, doors and windows.

The average builder will usually charge around £150 per day but will usually work in a team of at least 2 to 3. For a garage conversion you will need a few different trades to complete your job. A builder to help with any structural issues before you start the renovation. An electrician to install the cabling, sockets and lights. A heating engineer or plumber to install the radiators. A flooring specialist for the flooring. A joiner for any boiler/meter encasement, a plasterer and decorator for the walls and ceiling. As you can imagine, the difficulty in organising this number of different tradesmen can cause the project to drag on for weeks and sometimes it's better to simply hire a larger company to do all of the work at higher cost.

Below are some estimated costs of having your garage converted into a living space:

Job Description Avg. Cost Duration
Average cost of a single garage conversion £7500-£15000 3-5 weeks
Internal wall removal & RSJ £750-£1500 1-2 days
Damp proofing and insulation £500-£1000 1-2 days
Concrete and/or screeding £500-£1000 2-4 days
Flooring £400-£750 1-2 days
Garage Door Replaced with Window £1000-£1500 2-3 days
1 Window & 1 Door £1000-£1500 1-2 days
Boiler/Meter Encasement £1000-£1500 1 day
Build stud wall & added insulation £500-£800 1-2 days
Plumbing, Heating & Electrics £1500-£2000 3-5 days
Plastering £500-£800 2-3 days
Painting & Decorating £400-£600 2 days

Cost Breakdown

Individual costs of a garage conversion- Total Cost: £10,000






Waste Removal


If the garage you are converting is integral to the property or attached, then it is unlikely you will require full planning permission, it will just be a case of building regulations. As a general rule of thumb, garage conversions really only require planning permission if they are large and detached from the main property. However, you should in all cases check with your local authority before planning any home improvement project.
A professional Builder can complete a typical garage conversion in around a week or two depending on the amount of work involved, carrying out work such as damp proofing, floor raising, wall removal, and window/door installation. However additional work such as flooring, heating, plastering and decorating can add 2-3 more weeks onto the overall job duration.
Yes, all garage conversion projects that involve turning a garage into a habitable room will require building regulations approval from Building Control before any work is started.
Builders will tell you that they will obtain building regulation approval for you, however, the responsibility for building regulations approval always lies with the homeowner. If the contractor you hire agrees that they will obtain building regulation approval on your behalf, you need to ensure that you get this in writing from them.
Building Regulations approval is much quicker than planning consent and can sometimes be obtained in just a few days if you use a professional builder or architect that has an existing relationship with the Building Control department.