Have you ever thought how nice it would be to have an extra room? Do you long for a guest bedroom for visiting family and friends, or are you working from home and could use a space that offers some peace and quiet? Whatever purpose you’d like to use it for, installing a summerhouse or garden room is a lot cheaper and a lot less hassle than building a house extension or loft conversion.

Garden summerhouse painted in Protek Rose Pink

How much does a summerhouse cost?

With prices from as little as £2,500, there are all sorts of options available, including some that are fully insulated with electrics, plumbing, beds, kitchens and wood-burners. Here’s what to consider before you invest in a garden room and how to go about getting the right one for your needs.

Do you need planning permission for a summerhouse?

Before you begin, find out if you require planning permission. It all depends on where you want to position your garden room as well as where you live. Your new room will fall under permitted development and so won’t need planning permission if it does not contain sleeping accommodation and is single storey with a maximum eave height of 2.5m. The overall height must not exceed 4m for a dual-pitch roof and 3m for any other type.

If the room is within 2m of a boundary, the maximum height is 2.5m. It must not be located forward of the main front wall of the original house as it was first built or as it stood on 1 July 1948. Also, no verandas or balconies, and raised decking can’t be higher than 30cm. Anything else will need planning permission, including if you live in a national park, conservation area or listed building, a flat, maisonette or any other building that isn’t a house.

"Size-wise, your garden room won’t need planning permission if the building doesn’t take up more than 50 per cent of your garden," says Anna Sippel, marketing manager at Waltons. "Think about access too, as well as making sure you don’t block any natural light for your neighbours. Even if you don’t need planning permission, you’ll want to keep on their good side. A specialist company will be able to carry out a site survey to measure up and check for any potential issues regarding planning and building control. Don’t forget to insure your garden room and its contents too."

Key summerhouse considerations

Decide what you want to use the summerhouse or garden room for, as this will help you determine which materials, fixtures and fittings you need. When it comes to the windows and doors, look for powder-coated aluminium models with energy-efficient double glazing.

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Also, if you’re going to spend a fair amount of time in the room, ensure it’s properly insulated with floor, wall and roof insulation to keep it at a comfortable temperature all year round. Think about adding lighting, heating, electrics and possibly even a water supply to make it a truly multifunctional space. And don’t forget security, as you may be storing valuable equipment inside – consider installing anti-pick locks, security screws on windows and perhaps even integral window bars and security cameras.

Where should you site the summerhouse?

Work out where the sunlight falls during the day and then you can decide on the optimum position for your new garden room. If you’re working in there all day long, for instance, you’ll want to make the most of the natural light during the hours of 9-5. If, on the other hand, you’d prefer to use it as a home gym after work, placing it so the room catches the evening sun may be a better option.

Do you want it to be positioned away from the house (maybe if it’s for work or for the kids to hang out with their friends) or do you want it closer to your property so it’s easier to carry items back and forth? Wherever you choose to locate it, bear in mind that if it’s more than 2.5m tall at the eaves, it has to be more than 2m from the boundary to avoid planning permission.

Decide what you are going to use the summerhouse for

A garden room can be used for all sorts of activities and its intended purpose will largely dictate its size, cost and the elements within. A home office, craft space, teen den or spare bedroom will likely benefit from an electricity supply, at the very least, so you can recharge and power any computers, printers, sewing machines, TVs, and games consoles, or reading lamps and electric blankets.

If the room is to be used as a home gym, it may be that you only need it to be well insulated with comfortable flooring underfoot. A games room or space for entertaining could be more basic while a spare bedroom may require planning permission so always check before you splash out on the furniture and home comforts to make it cosy.

What do I need to budget for when installing a summerhouse?

Work out your maximum budget and stick to it. Factor in the cost for the garden room as well as preparing groundworks (a concrete base is best), installation costs, labour and then the price of kitting it out with all the extras you need. Buy the best quality you can afford and consider companies that specialise in these sorts of things rather than off-the-peg high street buys.

If you need planning permission and building regulations inspection and sign-off, then you’ll need to allocate some of your budget for this too. Other costs can include delivery, site clearance and the foundations.

‘The size of your summerhouse will depend on the intended use – an office can be a compact 3m x 3m. For a gym, you’ll need at least 12 sq m. For maximum versatility, invest in the biggest garden room you can afford. You never know, a craft hobby might become a business, while an office could double as a kids’ hangout.

The best-insulated garden rooms can be used all year round and accommodate plenty of extra storage space. Decluttering your home and having a bonus room in the garden to enjoy – now that can add significant value to your property.’

Summerhouse ideas

A shepherds hut can make a great garden room

Sometimes it's worth thinking outside the box. A shepherds hut can make a great garden room. Shepherd’s huts are ideal for overnight guests and can be fitted with bunk beds, wood-burners, showers and kitchenettes. The one above is The Snug (from £23,400) by Plankbridge

Your summerhouse is perfect for hobbies

Turn your space into a spot for hobbies and really make it your own. Garden Trading Aldsworth potting table, £350, John Lewis & Partners

Garden rooms can be multipurpose spaces, such as a guest room/study

Garden rooms can be multipurpose spaces, such as a guest room/study. Eclipse 575 Eleanor Vinyl, £22.99 per sq m; Bali wooden bed frame in white, £199.99, both Carpetright


Hayley Gilbert is an award-winning interiors journalist with 25 years' experience writing about everything from blissful bathrooms to the coolest kitchens. Publications she has written for include Good Homes, Country Homes and Interiors, House Beautiful and The English Home.