Garage Extension Cost

Garage Extension Cost Calculator

How Much to Build a Garage?

On average, you can expect to pay between £4,500 and £13,500 (incl. labour and materials). The exact price you're quoted by a builder will mainly depend on the type and size of the garage.

Since costs can vary significantly, the easiest way to get an accurate idea for your project is to post your job and get free quotes from local builders. Comparing multiple quotes ensures you find the right builder at the right price.

But what does this cost include?

This includes the costs of materials and hiring a builder to carry out the work. The specific type of garage, the quality of work, and the size of the installation can all affect the final price. However, once completed, you'll not only have somewhere safe and secure to store your vehicle but it will also be protected against the elements when not in use.

What can increase the overall costs of a garage?

Naturally, the larger the garage, the higher the costs. Similarly, if you want a high-quality finish, or an expensive garage door, then expenses will increase.

Price to Build a Garage

Here we look at the different types of garage extensions you can build and their estimated costs:

Concrete Prefab Garage Costs

A prefabricated garage (known as a prefab), is a factory-made kit garage. These are different to self build garage kits as they are already assembled for you.

A prefab is the cheapest and easiest method of installing a garage onto your property.

Starting prices for the kits are around £1,200 and go up as far as £5,000. For a simple single concrete prefab garage for the kit alone, it costs around £1,200, and a double concrete garage will start at around £3,000.

Metal Garage Costs

Although hardwearing metal garages can last over 20 years, especially if they're well looked after, generally speaking they're of lower quality than more expensive alternatives.

Prices for a single metal prefab garage can start from as little as £250 for an unknown brand, reaching up to around £2,500 for a double width and higher quality option.

Wooden Garage Costs

A wooden prefab garage kit is the second most financially accessible option for prefab kits on the market.

Starting at around £150 and ranging in up to £2,000, it is by far the cheapest option to those looking for a quick, easy build garage extension.

Brick Garage Costs

A brick garage is a longer-lasting, higher-quality garage.

The typical starting costs of a UK-sized garage extension, built from brick, with a flat roof will start at around £4,500. This is by far the most common form of garage extension chosen. If built well, they can last generations and only require periodic maintenance such as replacing the felt every 10 to 20 years to help avoid leaks from rainwater etc.

The length of time needed to build a garage extension will depend on factors such as the size of build and how many tradesmen involved, with labour fees varying by region. On the assumption there aren't any unforeseen issues, such as delays due to weather conditions or material supplies, a single garage can be completed within a 2 week window, whereas a high-quality double can take a month to finish.

Garage Roof Prices

Garage roof costs are important when it comes to overall price.

There are multiple options for roofing when it comes to a garage, depending on what you like, want and what budget you have:

Cost of a New Garage with a Pitched Roof

A pitched roof is angled at a pitch, similar to those present on houses. They can be either sloped on one side or both.

A standard pitched roof single garage with a tiled roof will begin at around £5,000. However, this price will increase with the quality of the tiles, with some as much as £20,000 for a double-pitched garage, with high-quality roof tiles.

Cost of a New Garage with a Flat Roof

A flat roof is usually constructed of felt and tar, spread over a timber frame. The timber, felt and tar can often be purchased together within a “flat roofing kit”; these start at around £250 for a kit big enough to build a single detached garage roof.

If you wish to purchase these items separately, it will cost around £50 for the timber, £150 for the felt, and £50 for the tar.

Supply Cost to Build a Garage

Now we're moving on to supply costs for a garage build! Supply costs within building a garage will be varied depending on your choices.

What do the supplies for a garage include?

Beyond the main construction method and the differing styles of roof, we have doors, foundations, and internal structures, which can also affect the price.

Let's take a look at the supply costs:

Prefab Kits

First up are prefab kits, here are the different garage kits available:

Metal Garage Prefab Kits

A metal prefab’s general materials will usually consist of the kit itself. This will include the panels for the walls, roof and fittings (such as screws and bolts).

The prices will range from £250 up to £1,500 for basic kits.

Concrete Garage Prefab Kits

A concrete prefab is similar to a metal prefab when it comes to the general materials. When purchasing the kit, it'll often come with the all fittings needed for construction.

The prices of concrete prefabs range from £1,000 up to £3,000 for basic kits.

Building Materials

Here are the building materials you'll need to build a garage:

Blocks

Blocks are by far the cheapest option for a custom-built garage. If rendered, a block garage will look just the same as a rendered brick-built garage but at a fraction of the cost of using standard bricks.

How many blocks will you need to build a garage?

Depending on the size of the garage and design, the number of blocks needed varies. On average around 500 blocks will be required for a single UK sized detached garage.

Blocks will usually cost around £100 per 54 block sets, meaning they cost just under £2 per block.

Brick

Bricks are the middle ground when it comes to the style of blockwork chosen for garage building. Bricks come in a multitude of colours, sizes, and even shapes.

The standard size of bricks, called “house bricks”, are the most common used, with red being the most common colour.

This choice of bricks is usually around £500 to £1,000 per 1,000 bricks and sold in groups of 250, 500, 750, and 1,000 bricks.

How many bricks are needed to build a garage?

A standard single detached garage will take on average around 5,000 to 7,500 bricks, depending on the complexity of the design.

Sand

Why is sand important when building a garage?

When building a brick or block structure, sand is required to make mortar to join the blocks together.

On average, a single garage will take around 1 x tonne of sand per 1,000 bricks. Although note this number doesn't include the sand required for making a concrete foundation.

Sand is not a very expensive material, so affordable builder’s grade sand will only cost around £50 per ton.

Cement

Cement is the other ingredient to mortar, other than sand. For every five parts of sand used, one part of cement is needed. The cost of cement is substantially greater than that of sand, costing around £5 per bag.

How much cement do you need to build a garage?

For a complete single detached garage, it will take around seven bags of cement; this means the total cement costs would be around £35.

Garage Roof Material Costs

Once you've decided on a pitched or flat roof, you also need to consider the material of said roof.

Below we break down the different options:

Plastic & Metal Corrugated Sheet

Plastic corrugated roofing sheets are often a cheaper and easier alternative to using a fully constructed flat roof. They still require a timber frame to be fixed onto, and if taking into account the quicker time of construction, a lot of costs can be saved in labour.

The standard corrugated plastic sheets will cost around £100 for a 2.5 m x 5 m sheet. For the metal equivalent, it will increase the price up to approximately £150 per sheet.

Roof Tiles

Roof tiles vary in price from around £1.85 per tile, up to about £5 per tile for the higher quality custom coloured varieties.

How many roof tiles will you need?

The standard single garage with a pitched roof will take around 1,200 to 1,500 tiles. This would usually cost (with bulk purchase discounts) around £500 for 1,000 tiles, for a standard clay tile set.

Garage Foundation Costs

The simplest type of garage foundation is a concrete slab, made from a mix of cement, sand, and coarse gravel. The exact quantity of materials depends on the slab size and thickness; for a typical single-car garage, a 30cm (0.3m) thick slab is standard.

For a slab of this size (approximately 3.6×6m), you will usually need around 3 tonnes of gravel/sand mix and 8–10 bags of cement. Gravel/sand mix costs around £50 a tonne, keeping the total material cost roughly the same as before.

Therefore, the total cost of materials to lay the foundation slab will be around £125, not including labour or other construction costs.

Garage Door Costs

All garages need a door in order for a car, and person, to gain access. There are multiple types of door styles to choose from; each one has its varying styles, prices, and uses.

Here's a list of garage doors to choose from:

Up and Over Garage Door

The most common style of garage door used is an “up and over” type.

What's an up and over garage door?

This means the door will open from the bottom and lift upwards sliding back into an area within the ceiling.

By far these are the cheapest and easiest solution to install, with prices starting at £150 and ranging as high as £1,000 for an electric-assisted model.

Roller Garage Doors

Roller doors are the second most popular style of garage door.

These are constructed of strips of wood or metal, and open up from the bottom, into a roll positioned at the top of the door opening.

Being more complicated to install and having a more complex design, a roller door's price is greater than an up-and-over style.

How much are roller doors?

The price of a standard roller door will usually start at around £500 and can increase in price up to around £5,000 for an ultra-secure electrically assisted metal roller door.

Sectional Garage Doors

A sectional garage door looks more like a normal door than a garage door, being constructed of various panels and having different ways to open them.

A sectional door is one of the highest-priced garage doors on the market. For a standard tri-folding single garage door, the prices usually begin at around £1,000.

Additional Garage Extension Costs

Materials and labour are not the only costs to consider when building a garage. Building any structure will have additional expenses.

What are the additional costs when building a garage?

If you require your garage to have electricity, you'll have to employ an electrician to fit the supply; this will cost around £150 per day.

Here are some security measures you can add to your garage:

• Security system — Installing a home security system costs £500.
• Outdoor lighting — Improving your home's outdoor lighting costs £200.
• CCTV — To boost your home's security, installing CCTV costs £350.

After the garage is built, you may want these additional jobs done, too:

• Adding new or replacing old guttering — To repair or replace your guttering costs £215.
• Adding a concrete driveway — To freshen up your home's exterior, adding a new concrete driveway costs £3,500.

Costs of Hiring a Garage Extension Specialist

When hiring any tradesman for building work, you need to consider what specific jobs actually need doing, as not all tradesmen can handle the same types of work. Building a garage is made up of multiple different trades.

Where should you start?

The most obvious place to start is garage-building specialists; however, this will depend on what style of garage extension you have chosen.

Below is a list of various tradesmen you may require and the jobs they will be undertaking:

Architect or Designer

Why would you need an architect for building a garage?

When planning a new garage extension, unless using a prefab, building designs or drawings will need to be created. Usually, a specialist designer or architect creates the plans; in order to make sure the correct materials, the correct style is used, and you get the results you want.

How much will garage designs cost?

This will take up a large percentage of the labour costs, considering it will be one of the smaller jobs involved. The cost to hire an architect or specialist designer usually is around £200 per day.

However, they would usually charge by a completed job rather than per day. This would be around £400 to £1,000 for a completed design, drawing, and technical specifications.

Concrete Layer

These are hired when you require a concrete slab for the foundation. Most garages, regardless of choice, will require a form of foundation, and the most common being a concrete slab.

How much will a concrete layer cost on average?

A concrete-layer will usually cost you around £75 per day.

This will depend on the skills and experience of the tradesman.

Generally, this will only take 2 days to complete the concrete work for a single standard-sized garage. This can increase to up to 6 days if a driveway extension is also planned in concrete.

Bricklayer

These contractors are hired for the construction of brick buildings. They can also often be used in constructing a foundation for the garage. Using a specialist bricklayer, who is experienced in building garage extensions, is often the best option when you want a high-quality, long-lasting garage.

How much do bricklayers charge?

A bricklayer's price for labour usually ranges from £75 to £150 per day, depending on the complexity of the job, the skills they have, and the experience they bring to the job.

General Builder

A general builder is often used to lead the entire project. They can hire and control subcontractors such as bricklayers and carpenters in order to complete the work.

If building a prefab garage extension, a general builder is often the best choice due to the robust nature of their experience and the labour price, which can be offered.

What will a builder cost?

A general builder will usually cost around £100 to £150 per day to hire, depending on the level of job required, the skills they possess, and the amount of experience.

Tarmac Specialist

Why would you need a tarmac specialist?

Once the garage has been built, it is often necessary for a driveway to be extended, if not created from scratch. In order to do so, you could use the concrete layer (if hired for the foundations); which if laid during the foundation, could save some money.

This will depend on the style of driveway required. If you'd like a tarmac driveway installed, a tarmac specialist will usually cost around £125 per day, depending on the level of experience and qualifications they possess.

Electrician

An electrician is usually required at the end of the build process if an electrical supply is required. From lighting, electrically assisted doors, and alarms to CCTV systems, an electrician would often be able to assist in the installation of multiple garage upgrades.

The average required time to hire an electrician would be for around 1 to 3 days, depending on the amount of work required.

How much would an electrician cost?

The day rate for an electrician often starts at around £125 per day, depending on their qualifications and specialities.

Labour Cost to Build a Garage & Timescales

One of the most important factors when considering any building work is obviously timescale.

No one wants a job that drags on indefinitely with no idea of when it will be completed.

Also..

The longer a project takes to complete, the greater the final price. Garage extensions are no exception.

Second to this is the price of labour. However, the timescale has a direct effect on the cost of labour, as the longer a job takes, the longer you will be required to pay your selected tradesman.

What can affect timescale?

There are multiple factors which can affect the timescale. The most obvious being the complexity of the project, the size of the build, and the final quality of the garage. Choosing to build a brick built garage extension will take longer than a prefabricated kit, although both still depend on experience and the size of the project.

A double garage will take longer than a single sized, at around 1 week for a single compared to 2 weeks+ for the double. However, these factors will also depend on the level of complexity in the plan, the skills the tradesman possesses, and the amount tradesmen needed to be hired for the project.

Factors That Impact Garage Extension Costs

The cost of labour takes the largest chunk out of your building budget.

However, the other expenses, such as materials, doors, windows, and internal decorations, will also take up a large section.

Materials can easily surpass the price of labour if only the finest materials are selected. The makeup of a garage is extremely customisable, with a choice of materials, colour, shape, design, doors, electric and security.

The planning of your garage will determine many of these factors; however, it is always best to keep a budget in mind before beginning preparations and buying materials. The size of the garage planned will have a direct effect on the final price.

What's the cost difference between a double and single prefab garage?

A double garage will usually cost around twice as much as a single, however, this is not always the case. A double-sized metal prefab kit begins at £1,000, and the single matching equivalent would begin at around £500.

What else do you have to consider?

Another consideration is the difference in price between an attached and detached, built garage. Attaching a build to your existing property will substantially increase the planning costs and overall difficulty of the job. It is therefore advisable to look into the possibilities of a detached garage wherever possible.

Let's compare the costs of an attached and detached garage!

For a basic single garage extension, attached to your existing building, it will usually cost around £1,300 for materials and £3,500 for labour.

Conversely, for the equivalent single detached garage, it will usually cost £1,500 for materials and £3,000 for labour.

This results in a price difference of £300, with the detached version costing £4,500, and the attached version costing £4,800.

This price difference will often increase as the size and complexity of the garage increases. The costs for planning the project and disposal of waste after the completion of the build, should also be accounted for in the budgeting stage.

Waste disposal will usually consist of hiring a skip. A skip is a large metal container used as a bin, for the disposal of building waste. Skip hire costs around £150 for a single skip hired for a week. Included in the price of the hire, is usually the cost of collection and disposal of the waste.

What's Involved in Building a Garage Extension?

Construction work such as a garage extension isn't suitable for a DIY project unless you're an experienced builder. It's physically demanding and far more complex than many people realise!

As part of the initial stages, it's recommended that you obtain at least three quotes from different tradespeople, as this will help you decide who's best for the job to ensure value for money. At MyJobQuote, you can find garage and outbuilding specialists near you for further information (and no further commitment).

Below we've outlined the main steps involved in the construction of a new garage in the UK.

Before the Job Starts

• Budgeting and Planning — Carefully decide on your budget, including cost of materials, labour, and additional expenses. Decide whereabouts you are positioning the garage extension and the design you have in mind. Unless you're using a prefab kit, hire a specialist to draw up detailed plans in advance.

During the Job

• Laying the Foundation — Clear the site area, dig your foundation and lay down a concrete base. Drying times depend on weather conditions and the strength of cement being used.
• Construction — How to go about building the garage will depend on whether it's a prefab kit or a brick-built garage, the latter involving laying brickwork, roof supports, and internal support.
• Roof Installation — Fit the roof accordingly, again depends on style a flat roof is often quicker to install, whereas tiled roofs require additional supports.
• Fixtures and Fittings — This includes everything from the lighting and electricity, to flooring, internal doors and fitting storage space. Some tasks may need professionals, such as electricians.

After the Job

• Security — You may also wish to call upon a security firm to assess your need for additional lighting and motion sensors, secure lock fittings, or to install CCTV.
• Enjoying Your Garage — Whether it's to keep your transport safe, add extra storage space, or spend some quality time relaxing or doing the things you love, it's time to make the most of your new extension.

Building Regulations & Planning Permission for a Garage Extension

Before starting any structural work such as adding a garage extension, you need to consider building regulations and any rules governing outbuildings, which include sheds and garages.

Most outbuildings are considered to be permitted development, so they do not need planning permission, but this is subject to a number of limits and conditions:

• The garage should not be built on land forward of a wall forming the principal elevation of the dwelling house.
• The garage also has to be single-storey with maximum eaves height of 2.5m and maximum overall height of 4m for a pitched roof, 3m for other roofs, or 2.5m if within 2m of the property boundary.
• In addition, if you want to avoid planning applications, you need to avoid any verandas, balconies or raised platforms.

As a general rule, you won’t need planning permission providing the garage is no more than four metres in height. The garage also needs to take up less than half of the land around your existing property. However, there are exceptions, such as if your property is a listed building or within a conservation area.

If you are unsure, always check with your local planning department first.

Can You Build a Garage Extension Yourself?

When it comes to a prefab garage extension, the concept is similar to that of flat-pack furniture, just on a much larger scale. Although realistically unless you're experienced in such DIY projects, you will be safer hiring a specialist builder to help complete the job.

Prefab builds usually require more than one person, so if you do go it alone you will need to call in some favours. For example needing two people to help lift and hold the panels into place, while a third then bolts them together.

As for a brick-built garage extension, this is an even more complex process than installing one that's already a part-built construction.

From digging the foundations to installing a roof, carrying out any electrical work and having someone lay the actual brickwork to begin with, there are a number of skills required - not to mention adding any fixtures and fittings.

Aside from the physical work itself, there's a lot of elements to organise. Unless you've previously worked in project management within a similar environment, it's recommended to hire a project manager to oversee everything on your behalf.

What Are Self-Build Garage Kits?

Self-build garages are a time-efficient way of building a new garage, although they can take more effort to complete than a prefabricated kit. Self-build options are designed as a fully DIY process, however, unlike many prefab garages they still require a concrete foundation.

They are also ideal for a customisation, as can be purchased in a range of materials (timber, brick, steel) and allow for individual modifications such as extra insulation or replacing the replacing the garage roof with an improved alternative.

Garage Removal Cost

If you're building an extension as a replacement to your old garage, then having the previous one removed properly should be left to a professional.

Hiring a tradesmen experienced in garage demolition will ensure they carry out the work safely and efficiently, as well as them being able to arrange any skip hire to dispose of the waste on your behalf. The average cost is around £2,000 and will take between 1 and 2 days.

Checklist: Hiring a Builder for a Garage Extension

Before opting for a builder to work on your garage extension, you should consider some factors that may affect not only the cost, but give you confidence that you've chosen the right contractor for the job.

Below is a checklist to help you when searching for your tradesmen:

• Do they have the relevant qualifications? Depending on the tradesman hired, these can be in the form of CSCS certification, City and Guild levels, or even college-gained qualifications such as HNCs.
• Are they covered by public liability insurance? One of the most important considerations when hiring any builder is their insurance. While public liability insurance isn't a legal requirement, any reputable tradesmen will have themselves insured accordingly, as it covers in the event of accidental damage or personal injury.
• Does the tradesman offer a guarantee? This would be a guarantee on the quality and longevity for the work they are going to undertake, which will add peace of mind and to ensure you're happy with the job before they finish.
• Can they approve building control sign-off? Many builders are able to self-certify their work, check this is the case for your chosen tradesmen and ask they liaise with your local authority for a Building Regulations Compliance Certificate.
• Have you asked for evidence of previous work? If they have references from previous clients, photos, or a portfolio of their work on sites such as MyJobQuote, it will prove they are proud of the level of skill they can provide.
• Do they have positive reviews? In addition to their portfolio, by checking on MyJobQuote choose a company with positive reviews and read what previous clients have to say. Alternatively, ask friends and family for recommendations.