What counts as permitted development for an outbuilding?

In England, many garden cabins, log cabins, shepherd huts and off-grid shelters can be built without full planning permission under what are known as permitted development rights. These rights allow certain minor works to proceed without a formal application, provided you meet a clear set of limits. The rules are generous but not unlimited, and getting them wrong can mean enforcement action later. This article walks you through the practical checks – eaves height, total coverage, distance from boundaries and more – so you can plan with confidence. Always confirm your specific proposal with your local planning authority, but the framework below is the place to start.

Height limits: eaves, ridge and the 2.5m boundary rule

For a single-storey outbuilding with a dual pitched roof, the maximum overall height is 4 metres. For any other roof type – flat, mono-pitch or curved – the maximum height is 3 metres. There is no separate eaves height limit for outbuildings under permitted development; the overall height is what counts. However, if any part of the building is within 2 metres of a boundary, the entire structure must not exceed 2.5 metres in height. That often rules out a full-height log cabin close to a fence. If you want a taller cabin, position it at least 2 metres from the boundary. Shepherd huts are often on wheels, which can sometimes bring them under caravan rules rather than outbuilding rules – but if a hut is static and used as an outbuilding, the same height limits apply. Off-grid shelters with sloping roofs should be measured at their highest point.

Coverage and positioning: the 50% rule and where you can build

Permitted development for outbuildings requires that the total area of ground covered by buildings within the curtilage of the house – excluding the original house itself – does not exceed 50% of the total land area around the original house. This includes existing extensions, sheds, garages, greenhouses and any new cabin. So a large garden may give you plenty of room, but a small urban plot can quickly hit the limit. Also, no outbuilding can be forward of the principal elevation of the original house, or forward of the side elevation if that side faces a highway. A cabin at the bottom of the garden is usually fine; one in the front garden is not. Think of the principal elevation as the main front of the house, even if you rarely use that door.

Use, special areas and restrictions

The outbuilding must be incidental to the enjoyment of the house. That means it can be a home office, gym, art studio, guest room or storage space. But it cannot become a separate dwelling – so no self-contained kitchen, bathroom and sleeping area that could be let out or lived in independently. If you install a kitchen and a shower and use it as a holiday let, you will likely need planning permission for a change of use. Shepherd huts and off-grid shelters used as occasional guest accommodation are usually fine, but permanent residence is a different matter. In conservation areas, Areas of Outstanding Natural Beauty, National Parks, the Norfolk Broads and World Heritage Sites, permitted development rights are more restricted. There, you cannot build an outbuilding on land forward of a wall forming the principal elevation, and stricter material and size limits may apply. For listed buildings, permitted development rights are removed entirely – you will need listed building consent and planning permission.

Materials, drainage and building regulations

Under permitted development, the outbuilding should be constructed using materials that are similar in appearance to the existing house. That does not mean identical, but a bright orange log cabin next to a red brick house might raise eyebrows. Also, if your cabin has sleeping accommodation, or is over 30 square metres in floor area, building regulations may apply – especially for electrical work, drainage and structural safety. Off-grid shelters with composting toilets or solar panels may need separate approval for waste and electrical systems. Even if you do not need planning permission, you must still comply with building regulations and any restrictive covenants on your title deeds. A quick check with your local building control team is always worthwhile.

Practical steps before you build

• Measure your garden and calculate the total footprint of all existing outbuildings and extensions. Check you stay under 50% of the curtilage.
• Check the distance from your proposed cabin to every boundary. If any part is within 2 metres, keep the total height under 2.5 metres.
• Confirm the principal elevation – usually the front of the house – and make sure the cabin is behind it.
• Look up whether your property is in a conservation area, AONB, National Park or World Heritage Site. If so, stricter rules apply.
• Consider the use: if it will be a separate dwelling or holiday let, apply for planning permission first.
• Talk to your local planning authority’s duty planner. A quick call can save you thousands.

Permitted development is a useful freedom, but it is not a free-for-all. With careful planning, most garden cabins, log cabins, shepherd huts and off-grid shelters can be built without full planning permission. Just remember the three key numbers: 4 metres overall height (or 3 metres for other roofs), 2.5 metres if within 2 metres of a boundary, and 50% total coverage. Get those right, and you can enjoy your new space with peace of mind.