Outbuildings are becoming more and more popular as home offices, workshops, studios, summerhouses, or as a playhouse for the kids. Whatever the use, here's the average cost to build an outbuilding in the UK.

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The average cost to build an outbuilding in the UK starts from around £6,500 for a prefab timber summerhouse up to around £22,000 for a brick-built garage.

However, costs will vary widely based on factors such as:

• Size

• Materials

• Intended use

Whether you're considering a garden office, a brick-built garage, or a timber summerhouse, understanding the project costs before you get started is essential.

Read on for all you need to know about the cost of an outbuilding in the UK.

How much does an outbuilding cost in 2026?

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Cost of an outbuilding by type

The average cost of an outbuilding varies depending on several factors, including the type and size of construction you opt for, your chosen materials, necessary groundworks, and connecting utilities.

Here are some average costs of building various types of outbuildings:

• Prefabricated timber summerhouse: Between £2,750–£10,250

• Concrete garage: Between £4,200–£10,000

• Small garden office: Between £6,000–£9,000

• Brick-built garage: Between £17,500–£26,500

Outbuilding prices per project

There are several types of outbuildings to consider. However, cost is a deciding factor for many people, so let's look at how the project costs compare.

Brick outbuilding cost

Unlike other materials, such as timber, brick outbuildings can often take longer to build. This can potentially add to the cost.

However, you may want to consider using brick if you’d like a garden office or garage that matches the style of your house. It would be a more permanent feature than a timber summerhouse or shed.

• For a simple brick-built garage, you can expect to pay on average around £22,000

• To upgrade the specification with better roof coverings, plumbing for an outdoor tap, or other features, costs can reach as high as £26,500

Breeze block shed cost

Breeze blocks are a great option if you're looking to get some of the same advantages of a brick outbuilding but at a fraction of the cost.

• Expect to pay around £100 for just over 50 blocks

• This brings the average cost per block to less than £2

• You'll also need to factor in around £3 per m² for mortar

For the blockwork itself, the typical concrete block shed cost is around £36 per m². This includes labour and materials but not all the other costs that come with building a shed, such as roofing, doors, or windows.

Do I need planning permission for a shed?

Find out when you need planning permission for a shed, what permitted development allows, and how size, height and location affect approval.

Learn more

Garden outbuilding cost

A garden outbuilding can be used for a whole range of different purposes:

• A private home office

• A peaceful summerhouse retreat

• A yoga studio or wellness space

• A hobby workshop

• Or simply, additional storage

The cost of a garden outbuilding will depend on the construction and roof type, but access may also be a factor.

For example, it could be more expensive if your new outbuilding is located at the bottom of the garden with limited access for the construction crew.

There may also be extra costs for connecting your garden outbuilding with services such as electricity and water, plus insulation.

• On average, expect to pay around £7,500 for a small garden office or studio

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What affects the cost of an outbuilding?

You'll find that several factors influence outbuilding costs. Here are the main ones to be aware of:

• Materials: Brick, concrete, timber, and prefabricated structures all sit at different price points, as will your choice of windows, doors, and roof

• Size and design: Larger or more bespoke designs will increase costs

• Utilities: Adding electricity or water connections adds extra expense

• Site access: Tricky access can push labour costs up

• Foundations: Complex groundworks can increase your overall costs

Hidden outbuilding costs to watch out for

In addition to the physical construction of your outbuilding, there are a couple of other costs to factor into your budget.

• Planning permission: Many outbuildings fall under 'Permitted Development' and therefore don't need planning permission, but not all. Be sure to check and budget for the cost of a planning application if needed

• Insulation and heating: If you intend to use your outbuilding year-round, investing in insulation and heating is a wise move

• Interior finishes: Flooring, lighting, and decor all add to the outbuilding project costs

• Maintenance: To keep your outbuilding looking good for longer, plan for the cost of a little TLC, especially for timber structures

Outbuilding ideas: Design and conversion inspiration

Explore the potential of your garden with our helpful outbuilding ideas. With design examples and conversion ideas to transform even the smallest of spaces.

Learn more

Whatever the purpose of your proposed outbuilding, such as a garden room, stylish summer house or something as simple as a plastic shed, at Checkatrade we're here to help you get a job done right.

Cost of hiring a checked tradesperson vs DIY

You might be tempted to build your own outbuilding as a DIY job.

A prefabricated timber summerhouse would be the most straightforward outbuilding as a DIY project, with prices starting from around £2,750.

However, constructing an outbuilding can be labour-intensive, and certain aspects, such as the foundations and any work involved with moving drains or connecting services, may require assistance from a checked tradesperson.

Hiring a building contractor committed to quality will ensure:

• A job done right

• Compliance with regulations

• Handling of complex tasks such as connecting utilities

• A warranty or guarantee on their work

Every Checkatrade job is backed by our £1,000 guarantee

Up to £1000. Eligibility criteria and T&C’s apply.

Builder day rates

Builders in the UK tend to average around £400 per day, but prices can vary depending on location and project complexity.

To ensure a fair and competitive price:

• Get a selection of quotes from checked tradespeople

• Make your choice of hire

• Ask for a written agreement or contract before work begins

• Follow our best practice on paying deposits

On Checkatrade, you'll only find trades who meet our high standards and pass up to 12 checks.

Outbuilding cost checklist

Ready to kickstart your outbuilding project? Use our handy checklist to get started.

• Decide on the purpose and size of your outbuilding

• Check whether you need planning permission

• Consider the materials, e.g., brick-built, timber, etc, and the utilities required

• Decide on whether insulation and heating are needed, and the interior finishes you want

• Remember to get a selection of quotes from building contractors covering your area

Outbuilding checklist to consider

• What size building do you require or have space for?

• What is the purpose of the new space?

• Will you need planning permission?

• What do you want the building to be made from?

• Will you require just a space or additional facilities like electric or water?

• Will you want to use the outbuilding in winter months?

• Have you shopped around for different tradespeople or suppliers?

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FAQs on outbuilding costs

Do I need planning permission to build an outbuilding?

Many outbuildings fall under the category of ‘Permitted Development’, which means that you shouldn’t need planning permission. However, there are strict criteria to meet. For example, the outbuilding can’t be used as accommodation or as a kitchen/bathroom, and it must be under a maximum size and height.

What is the maximum size of an outbuilding without planning permission?

Permitted development rules apply to the size, position, and use of an outbuilding. The structure should be:

• Only one storey high

• Less than 10 square metres big and more than 20 metres from your property if you live in a conservation area

• Either more than 2 metres from your property boundary or less than 2.5 metres high

• Not built to the front or side of your home if you live in a conservation area

• Not located in your front garden

For a full list of criteria, please refer to the Planning Portal website.

How much would it cost to build an outbuilding?

The average cost to build an outbuilding in the UK starts from around £6,500 for a prefab timber summerhouse up to around £22,000 for a brick-built garage. Costs will vary based on factors such as size, materials, utilities, groundworks, insulation, and heating.

How much does a brick outbuilding cost?

• A simple, brick-built garage costs, on average, around £22,000

• To upgrade the specification with better roof coverings, plumbing for an outdoor tap, or other features, brick outbuilding costs can reach as high as £26,500

What's the cheapest way to build an outbuilding?

A prefabricated timber summerhouse is a more affordable outbuilding option, starting from around £2,750.

How long does it take to build a new outbuilding?

It depends on the type and construction of your planned outbuilding, but your project should take between 1 and 3 weeks to complete.

Do outbuildings add value to a house?

A well-constructed, good condition, functional outbuilding, such as a home office or studio, can add value to your home, as it may be more attractive to potential buyers.

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