Garden room costs – how much is a garden building for a home office, gym and more

A modern garden room adds value to your property, making it a worthwhile investment

Garden rooms are more popular than ever. Blame being in lockdown, but increasingly homeowners are looking for cost-effective ways to extend the useable living space within their current homes. More space and a change of lifestyle without having to move house, who wouldn't want an extra room in the backyard?

A well-planned garden room provides a unique alternative to traditional home extension methods, creating more space for however you choose to use it. A garden room can be anything your heart desires, from a tranquil garden home office or yoga studio to a self-sufficient annex for extra accommodation – depending on your budget.

While a garden room might not add as much value to your home as a traditional extension or loft conversion, they take considerably less time, less intrusion and less investment – making a garden room great value for money.

Visit our garden channel to see all the latest ideas for improving outdoor spaces

How much will a garden room cost?

garden room with sofa

(Image credit: Future PLC/Claire Lloyd Davies)

 Costs of garden rooms can vary hugely due to the variety of materials used and the features included. Many brands offer construction and painting services, although this generally requires an additional fee.

We look to leading experts for the average costs of installing a quality garden room. Green Retreats garden room prices start at £15,745 for a complete and installed solution.

So what does that price include? That cost covers VAT, professional installation of base/foundations, 2.3m French or sliding doors, opening window, oak laminate flooring, internal wiring, 3 double plug sockets, lighting, heating and premium-grade insulation. Plus delivery within 100 miles of their factory.

Choosing the right supplier and contractor is key, because a poor quality building will cost you more in the long run. A company like Green Retreats is rated 5 stars on Trustpilot, the independent review site, and is  endorsed by architecture guru Kevin McCloud. Every one of its garden building comes with a comprehensive 10-year guarantee and is designed for a 30-year life to ensure confidence when you spend.

'Some garden room companies use concrete foundations' explains Jo van Riemsdijk from Modulr Space. 'These may or may not be included in the price. Find out what the garden room company needs you to do in order to be able to erect the building. Make sure you clearly understand all the costs associated. Prices can really rack up if you are not absolutely clear on what you might like as an optional extra.'

The smallest Modulr Space garden room unit starts at £17,500 + VAT which is fully fitted out and ready to go. A two room unit starts at £58,500 + VAT. A three room unit or anything over and above that is on a POA due to the bespoke nature.

Read more: Garden rooms – design ideas and expert advice to create an idyllic garden building

How can you build a garden room on a budget?

garden shed with table

(Image credit: Future PLC/Mark Scott)

 'The very cheapest option is ultimately a garden shed that you adapt to your own requirements' suggests Jo. 'This may work for some – but it will be cold. This will require regular maintenance to prevent it from rotting and there's no guarantee you wont get mice – or worse!'

‘There’s a cost to laying a good-quality foundation, but with reasonable skills you can keep the price of this low by doing it yourself,’ says Anna Sippel at Waltons. ‘You will need to pay a qualified electrician if you want electrics in there. But digging the power cable trench to their specification in advance will keep the price down.’

Related: Garden shed ideas – projects and designs for your own dedicated outdoor room

Will a garden room add value to my home?

garden room with sofa and chair

(Image credit: TGO3 Garden Room)

The short answer to this question is yes, garden rooms do add value – by increasing the square footage of a property's living space.

Leading property experts estimate adding a garden room can add 1.5 times their value to a home – depending on the quality of the build and costs of the installation. 'Whilst a lot of the value is attributable to the extra space it creates, a garden room is modern and stylish and adds to the whole appeal of the property' reveals Robert Ellis of Nutbrook Property.

'There is no doubt that the quality of the building adds significant value too. I would estimate that the value-added would be about 1.5x the cost of the building installation. The convenience value is also significant and must be considered for homeowners.'

How will a garden room add value?

'Traditional ways to add extra space at home, such as extensions and loft conversions, are huge projects that can be overwhelming and pricey' say the experts at Green Retreats. 'A garden room allows you to add extra space at home simply and cost-effectively.'

Sacrificing a bedroom to create a home office, gym or studio is not the most beneficial way to create alternative space. A garden room allows you to add extra space without removing valuable living areas from inside the house.

garden lawn with room

(Image credit: Modulr Space Ltd)

Having a dedicated home office is now a highly desirable selling point. 'Having a home office in the garden away from the house can now make or break a property deal' Luke Jackson reveals. 'People may not be commuting to the office every day, but they still like the structure of leaving the house to go to work. A garden room provides that physical and mental distance between home life and work life.'

Considering a home office outside? Read: Garden office ideas to create a serene workspace away from the house

Garden rooms have rapidly become so much more versatile over the past year. From garden bars and games rooms to garden gyms the potential is huge, with the right imagination – and budget of course.

Is a garden room worth the cost?

‘I think a garden room is a really fabulous thing to do,' says TV presenter and property expert Sarah Beeny. 'Ultimately if you don't look at the garden, you can't use the garden apart from on a really sunny day. We don't have that many sunny days in this country, so there's a whole load of square footage you're paying your mortgage or your rent on, but you never use. So you need to enjoy looking at it or use it in some way – a garden room is a really good way of doing that.'

'If you are considering sacrificing some of your outdoor space for a garden room make sure you have really considered how and when you will want to use it' advises Jo van Riemsdijk from Modulr Space. 'Any garden room should be an extension of your living space as opposed to subsequent to it. If you're intending to use your garden room all year round look to find a design that is well insulated.'

Jo says to ask yourself, 'Does the manufacturer use thermal glazing? How is the unit heated? If you intend on being able to use the space on the coldest days, choose a supplier who will be able to give you insulative U values. And clear indicators on how the space will be heated and whether it’s going to work for you.'

Contemporary garden buildings make a stylish addition to any outdoor space, making them an attractive feature to potential buyers. So if you can afford it, see it as an investment.


Tamara was Ideal Home's Digital Editor before joining the Woman & Home team in 2022. She has spent the last 15 years working with the style teams at Country Homes & Interiors and Ideal Home, both now at Future PLC. It’s with these award wining interiors teams that she's honed her skills and passion for shopping, styling and writing. Tamara is always ahead of the curve when it comes to interiors trends – and is great at seeking out designer dupes on the high street.