Outbuildings are becoming more and more popular, especially since the COVID pandemic. People all over the country are using them as garden offices, summerhouses or gyms. An outbuilding can serve so many purposes, making it a versatile addition to your home. Let’s explore how much they cost to build and what you need to consider in this guide.

How much does an outbuilding cost?

The cost of an outbuilding in the UK can vary significantly depending on factors such as size, the material you choose, complexity of design, and any additional features. On average, expect to spend £10,000 on a new outbuilding.

Type of outbuilding	Average cost
Purpose-built outbuilding	£10,000
Timber log cabin	£6,500
Prefabricated modular outbuilding	£1,500
Brick outbuilding	£24,000

Outbuilding cost per square metre

The cost of an outbuilding per square metre can range from £800 to £2,500 or more, depending on factors such as materials, design complexity, site conditions and location. Generally, larger outbuildings tend to have a lower cost per square metre, while smaller or more bespoke structures may have a higher cost per square metre.

It's important to consider not only the initial construction costs but also ongoing maintenance when you calculate the overall cost per square metre.

Factors that affect the cost of an outbuilding

• Type of outbuilding: While the average cost of an outbuilding is £10,000, some are much cheaper or more expensive than this. Prefabricated modular outbuildings can cost as little as £1,500, while a brick outbuilding could cost £24,000 or more.

• Size: As you’d expect, the bigger your outbuilding, the more it will cost. You’re more likely to need proper concrete foundations if your outbuilding is large, which will add to the final bill.

• Complexity: Simple, square or rectangular designs will be cheaper than outbuildings in non-standard shapes or with more than one room inside.

• Additional features: If you want a kitchenette or wet room in your outbuilding, or perhaps bifold doors, these extra features will drive up the cost.

• Where you live: One of the biggest factors affecting the cost of outbuildings is where you live, and you can’t do much about this one! Labour costs vary across the UK, with builders in London and the south east charging the most.

At HaMuch, we use our database of hourly and daily rates to estimate how much projects will cost all over the UK. Take a look at the table further down the page and find your nearest town or city to get a better idea of how much an outbuilding will cost in your area.

What can you use an outbuilding for?

Garden office or studio

Outbuildings can serve as tranquil and productive spaces for a home office or creative studio. Whether you're a remote worker, freelancer, artist or writer, a garden office or studio provides a dedicated environment away from household distractions. With ample natural light and a serene setting, a garden office can help you focus and be more productive and creative.

Workshop or hobby room

Outbuildings are ideal for housing workshops or hobby rooms, providing space away from the house for your to enjoy your interests and activities. Whether it’s woodworking, crafting or any kind of DIY projects a well-equipped workshop or hobby room offers the necessary tools, storage, and workspace to indulge your passions.

You can customise your outbuilding with any fixtures or fittings you need, such as workbenches, shelving or storage solutions, to tailor your space to your hobby.

Gym or fitness studio

Outbuildings can be transformed into private gyms or fitness studios, offering a convenient and comfortable space to exercise and stay active that’s bound to be cheaper than a gym membership in the long run.

A dedicated fitness space allows for uninterrupted training sessions at any time of day. Add exercise equipment, mirrors and sound systems to keep yourself motivated and ready to take on any kind of workout.

Guest accommodation

Outbuildings can provide additional guest accommodation, offering a comfortable and private space for visitors or extended family members. Add sleeping area with basic amenities as well as a wet room and you’ve got a welcoming space for guests when they visit.

However, remember that if you want to create a granny annexe that someone will use as self-contained accommodation at all times, this comes with strict planning permission requirements and building regulations.

Storage or utility room

Outbuildings are also great as storage or utility rooms, providing space to store tools, equipment, garden supplies or household items. Whether used as a garden shed or utility room, these outbuildings help declutter your main house and organise belongings efficiently.

With shelves, cabinets and storage solutions, they offer a convenient and accessible space to keep items secure and protected from the elements.

Summerhouse

A summerhouse is a perfect use for an outbuilding, offering a retreat for relaxation, socialising and entertainment. Add a pool or table tennis table and turn it into a games room, a TV for a home cinema or a bar and lounge area to create your ideal sociable space.

With our great British weather, a summerhouse offers a welcoming environment to unwind, entertain guests and enjoy quality time with family and friends in the garden even between rain and showers.

Do outbuildings add value to a property?

Yes, outbuildings can add value to a property. It depends on the size, quality and functionality, but most estate agents will say that outbuildings add value. Robert Ellis from Nutbrook Property told Green Retreats that an outbuilding can add 1.5 times the construction cost to the value of your home.

It’s always best to think beyond the value that could be added to your property when considering an outbuilding. Think about whether an outbuilding is worth it for you, whatever you plan to use it for. That will help you get the most value out of it.

Do you need planning permission to build an outbuilding?

In many cases, you won’t need planning permission to build an outbuilding. Outbuildings are often considered permitted development and don’t require planning permission provided they meet certain criteria such as size, height, and placement within the property:

• The outbuilding must not occupy more than 50% of the space around your home

• The total floor area must be under 15m²

• The eaves must not be higher than 2.5m

• The building must be single-storey with a total height of 3m

However, there are exceptions and limitations, particularly in conservation areas and listed buildings. It's best to check with your local planning authority to determine the specific requirements and whether planning permission is needed for your outbuilding project.

What is the 4-year rule for outbuildings?

The 4-year rule allows for certain outbuildings or structures built without planning permission to become lawful if they have been in place and continuously used for a minimum of 4 years. Homeowners can apply for a Certificate of Lawfulness to prevent their outbuilding from being subject to enforcement action.

However, the 4-year rule will expand to a 10-year rule from 25^th April 2024, meaning you’ll need to demonstrate 10 years of continuous use rather than 4. It’s always best to err on the side of caution and check whether you need to apply for planning permission before you start building your outbuilding so you don’t need to worry about retrospective rules.

Are outbuildings covered by buildings insurance?

In most cases, outbuildings such as garages, sheds, and garden rooms may be covered under standard buildings insurance policies as long as they are considered integral to the property and used for domestic purposes.

However, coverage may vary depending on factors such as the value of the outbuilding, its proximity to the main dwelling, and any additional features or utilities. It's best to review your insurance policy carefully and consult with your provider to ensure adequate coverage for your outbuildings.

What are the building regulations for outbuildings?

In many cases, you won’t need to follow building regulations for outbuildings, as long as the floor area they cover is less than 15m². However, if your outbuilding will be used for sleeping all the time, you will have to follow building regulations regarding the electrics, fire safety and more.

If you’re ready to get started with your outbuilding project, post your job with HaMuch now. We’ll send your enquiry to builders in your area who will be happy to give you a quote.

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