How much does a garden room cost? [What You Need To Know]

Garden rooms have been increasing in popularity in recent years due to the increasing number of homeowners looking to improve rather than move from their homes. In comparison to the price of traditional extensions or loft conversions, a garden room can be a cost-effective way of increasing the useable living space within your home.

A bespoke garden room costs, on average, between £16,000 and £34,000. The cost depends a lot on the size of the garden room, the materials used, as well as the fittings and features included.

In recent years, garden rooms have become an increasingly versatile way of creating additional space within our homes. Considering how underutilised garden space can become in colder seasons, it’s no wonder why an increasing number of homeowners are now unlocking the potential of their garden space with innovative garden rooms.

*This studio by Surman Weston was designed for a musician and a seamstress. See more* *here. Photography by Wai Ming Ng.*

But, there might be some red tape for a few homeowners so in this post I cover topics such as whether planning permission is required for a garden room, if a garden room can actually increase the value of your house (and by how much), and some key points to consider when designing your own garden room.

Do I need planning permission for a garden room?

You do not need planning permission for a garden room if the garden room falls within these permitted development limits and conditions.

Height

Single storey with a maximum eaves height of 2.5 metres.
A maximum overall height of 4 metres with a dual pitched roof or 3 metres with any other type of roof. However, if the garden room is within two metres of a boundary the overall maximum height is restricted to 2.5 metres.
No verandas, balconies or raised platforms - any platforms, such as decking, must not exceed 300 millimetres in height.

Location

Not on land that’s in front of the main front wall of the ‘original house’. The term "original house" means the house as it was when first built or as it stood on 1 July 1948 if your house was built before this date.

Size

No more than half the area of land around the ‘original house’. Again, be mindful that the term ‘original house’ refers to the house as it was when first built or as it stood on 1 July 1948, so if you or previous owners have already built an extension then this may have reduced your permitted allowance volume.
In National Parks, the Broads, Areas of Outstanding Natural Beauty and World Heritage Sites the maximum area to be covered by a garden room that is more than 20 metres from the house is limited to 10 square metres.

*Image courtesy of London Garden Studios.*

When planning permission is required for a garden room

Planning permission is required if:

Your home is a flat, maisonette or any other type of building other than a house.
The property you live in undergone a change of use to be converted into a house.
You live on designated land and would like the garden room to be to the side of the house (designated land refers to national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites).
The garden room is to be placed within the boundary of a listed building.

Disclaimer – please note this is introductory information and is not a definitive source of legal information. This guidance relates to the planning regime in England. Policies in your country may differ therefore if you are in doubt please contact your local planning authority.

*This timber outbuilding designed by Applied Studio houses a living space to enjoy the garden but also a sauna and* *shower. See more* *here. Photography by Nicholas Worley.*

Does a garden room add value?

In short, yes, a garden room does add value to your house. According to leading property experts, a garden room can add 1.5 times their value to a home depending on the quality of the garden room’s build and installation.

When choosing a garden room, you tend to have the option of an off the shelf modular solution, or a bespoke approach that is designed specifically for you.

The cheapest option is usually a modular garden room that can be adapted slightly to your own requirements. When exploring this option, it’s extremely important to have a good understanding of factors such as: whether there’s satisfactory foundation for the structure, if regular maintenance is required to prevent rot, and whether the structure is adequately insulated for use throughout the year. Choosing the right supplier is key, because a poor-quality garden room will inevitably end up costing you more in the long run.

A bespoke option will tend to be more expensive upfront, but it can be precisely tailored to your needs and lifestyle. Plus, a quality built, modern garden room can help towards increasing the value of your home due to the extra space it provides and the increased appeal to potential home buyers.

*St Mary’s House by Paul Archer Design. See more* *here*.

How to design a garden room?

Aside from the cost of purchasing the outbuilding itself, there are other costs to consider in your budget. By thoroughly considering how you want to use your garden room this will help in the process of determining the design of the space and subsequently the final cost.

A garden room should act as an extension to your existing living space and support your lifestyle. Start your design by determining what you want the space for, this could be a home office, gym, playroom, recording studio, maybe you’d like the space to be multi-functional. Once defined, you can then begin detailing the requirements of the space, this well help with clarifying important considerations and the design features that are needed.

As an example, if you’re planning a home office you may list requirements like the below and therefore need to consider the following :

Be able to work at any time of the day, throughout the year.
- Electricity supply to the garden room, light fittings that will keep the space bright and comfortable to work in, and the number of sockets and switches that you’ll need.
- Ensuring that you’ve got good internet access in the garden room.
- If using electric heating, you’ll need to consider the BTU output needed to adequately heat the space. It’s also important to have good insulation so that the heat is retained.
- You may also consider factoring in outdoor lighting and landscaping costs if a visible path needs to be created.
Space for my desktop computer and laptop, with a good view into the garden.
- Door and window security if valuables are being left in the space.
- Window, desk and socket placement to make the most of the view into the garden.
Storage space for books and stationery - ideally hidden, keeping everything tidy and minimal.
- Custom joinery for storage and desk could work well for the space, or an off the shelf item. Take into account whether the size of the desk and ergonomic chair will work in the space if you take this approach.