Summer houses: Planning permission explained

What counts as a summer house?

To start with, it’s often the case that “summer houses”, “garden rooms” and “log cabins” are all much the same. From an architect’s point of view, they can represent distinct types of structures with different design considerations. Typically, a summer house is focused on enhancing the appearance of outside spaces yet is often designed to provide a seamless connection between your property and the garden.

Meanwhile, the beauty of summer houses lies in their versatility. As a stand-alone structure that is well insulated, they can be designed for functional year-round use if you want to create a separate office space or have an annex for guests. They also make ideal rooms for art studios, gym spaces, or as bespoke sports solutions like this one by Golf Swing Systems that comes complete with a golf simulator. 

With the help of architects, summer houses are suitable for every type of property and are a worthwhile investment that can rejuvenate dead spaces outdoors. They can be designed and painted to complement the style and appearance of your home whether it is contemporary or older, be an integral part of a grand design or blend well with a period property. They are also great for creating a garden zone that is popular with homeowners and may appeal to buyers when you come to sell. 

Do you need planning permission for a summer house?

It is more likely that you will not require planning permission to erect a summer house on your land. Classed as “outbuildings”, they fall under the “permitted development rights,” within the UK’s general planning system. Under these rights, garden structures can be designed for purposes described as “incidental to the enjoyment of the dwelling house”, such as an office, hobby room, or recreational space. In layman’s terms, you might simply buy one readymade, design it yourself or ask an architect, designer or company to customise one for your home and garden. 

However, although permitted development allows you to make improvements and install summer houses without going through the full planning process, local authorities may interpret your intended plans differently. Permitted development rights may be restricted or removed in certain areas, including: 

• Conservation areas
• Areas of Outstanding Natural Beauty (AONB)
• National Parks
• Listed buildings
• Properties where permitted development rights have been removed by Article 4 Directions

When your summer house needs planning consent

Although it’s unlikely, if your summer house doesn’t qualify under the permitted development rights for the cases mentioned earlier, you’ll likely need to apply for planning permission with your local authority. Working with your architect can significantly improve your chances of planning success. They can design a summer house that complies with local policies and addresses any potential concerns you might have before submission.

Furthermore, even if your summer house falls under permitted development, obtaining a Lawful Development Certificate is recommended. This legal document confirms that your building is lawful and can prevent potential complications if you want to sell your property in the future.

How large can your summer house be without planning permission?

Under permitted development rights, the size of your summer house is subject to specific limitations. The total area covered by your structure must not exceed 50% of the total area of the curtilage of your property (excluding the ground area of the original house).

A summary of the maximum height allowances under permitted development include:

• Single-storey buildings must have a maximum eaves height of 2.5 metres
• No outbuilding can be built forward of the principal elevation of your original house (the wall facing the road).

For summer houses more than 2 metres from all boundaries:

• Maximum overall height of 4 metres with a dual-pitched roof
• Maximum overall height of 3 metres with any other roof type
• Maximum eaves height of 2.5 metres

• For summer houses within 2 metres of any boundary:
  • Maximum overall height of 2.5 metres regardless of roof type
  • Maximum eaves height of 2.5 metres

Additionally, the maximum total footprint allowed for all outbuildings depends on your property size. For most residential properties, these limits (while accounting for size and usage) are:

• For detached houses: Up to 30 square metres without building regulations approval (providing it’s positioned at least 1 metre from any boundary)
• For semi-detached or terraced houses: Up to 15 square metres without building regulations approval

Buildings larger than these dimensions may still fall under permitted development but will require building regulations approval even if planning permission isn’t needed. 

These height restrictions are designed to balance your aims to optimise a spacious garden building and protect neighbouring properties from excessive overshadowing or visual intrusion. While structures are measured from the highest ground level immediately adjacent to a property, if your garden slopes, measurements are taken from the highest point where the summer house meets the ground. 

Can you build a summer house next to a neighbour’s fence?

Positioning your structure near a boundary requires careful consideration of both regulations and neighbourly relations. While it’s technically possible to build near your neighbour’s fence, those limitations, once again, will depend on height restrictions mentioned before. If the roof goes above 2.5 metres, you must maintain a minimum distance of 2 metres from your neighbour’s fence while being mindful of future access for maintenance.

These restrictions, or party wall regulations, are in place to minimise the impact of garden buildings on neighbouring properties, particularly regarding limiting sunlight or disrupting views. When you’re at the stage of designing your outside structure, an architect often recommends sloped roofs facing the boundary to reduce height and impact. Out of politeness, you might discuss plans with your architect and neighbours before the project. 

What building regulations might you require?

Even if you don’t need planning permission, summer houses do need to comply with several building regulations, fire safety rules and local bylaws and covenants. The materials used to construct a room in your garden might impact planning permission and should be similar to those used in your main property.

Moreover, the intended use of your summer house will matter. While it’s feasible to use it as occasional guest accommodation (under permitted development), creating a separate self-contained unit would require planning permission and compliance with stricter building regulations.

Similarly, when it comes to installing electricity, water, or drainage, you may require additional permissions or compliance with specific regulations. Electrical installations, for instance, must comply with Part P of the Building Regulations.

Want help? Book a free discovery call

If you’re thinking about building a summer house, we can guide you through what’s possible, what needs approval, and how to make your idea work legally and practically. We can help you design one that works for your requirements and within the confines of your property’s space, size, design and unique character. Book a discovery call today and speak with a member of our expert planning team.