Guide
Garden rooms: planning permission and Building Regulations
Most garden rooms can be built without planning permission under permitted development, as long as they stay single storey, sit behind the front of the house, keep within height limits (2.5m within 2m of a boundary) and are not used as a bedroom. Under 15m² with no sleeping space, Building Regulations approval is normally not needed either.
Updated 3 min readBy the Solubius team
For houses in England, a garden room counts as an outbuilding. Outbuildings can often be built under permitted development, which means no planning application, as long as they meet a set of limits. Building Regulations follow a separate set of tests, and they depend mainly on the size of the room and whether anyone will sleep in it.
The planning limits
The Planning Portal and the government's technical guidance on householder permitted development set out the conditions. A garden room can usually go ahead without planning permission if:
- It is not in front of the house. Nothing may be built on land forward of the principal elevation, which is usually the front of the house facing the road.
- It is single storey, with eaves no higher than 2.5m.
- It keeps to the height limits. Overall height no more than 4m with a dual-pitched roof, or 3m with any other roof. If it is within 2m of a boundary, the whole building must be no higher than 2.5m.
- It has no veranda, balcony or raised platform over 0.3m high.
- It does not take up too much of the garden. Together with other extensions and outbuildings, it must cover no more than half the land around the original house.
- Its use is "incidental" to the house. A study, gym, studio or playroom is fine; separate living accommodation or a bedroom is not.
Where the rules are tighter
- Flats and maisonettes do not have these rights. The permitted development rules for outbuildings apply to houses only.
- Listed buildings. Any outbuilding within the grounds of a listed building needs planning permission.
- Conservation areas. Outbuildings between a side wall of the house and the boundary need permission.
- National Parks, Areas of Outstanding Natural Beauty and similar designated land. Outbuildings more than 20m from the house are limited to 10m², and outbuildings at the side of the house need permission.
- Removed rights. As with garage conversions, a planning condition or an Article 4 Direction can take permitted development rights away. On a newer estate, check the planning history before you commit.
Building Regulations
The Planning Portal gives two thresholds:
- Under 15m² internal floor area, with no sleeping accommodation: Building Regulations approval is normally not needed.
- Between 15m² and 30m², with no sleeping accommodation: normally not needed, provided the building is at least 1m from any boundary or is built substantially of non-combustible materials.
Above those thresholds, or if the room will include sleeping accommodation, speak to building control before you design it. Electrical work to power the room still has to meet the wiring regulations whatever the size.
Planning it around how you will use it
The rules set the outside limits, but the use should set everything else: where the light falls, how much storage you need, where the desk or the equipment goes and how warm the room has to be in January. We plan garden rooms from the use first, then fit position, size and interior within the limits above.
If you are unsure where your garden stands, the Planning Portal's interactive guide walks through the rules for your own situation.
Sources
Common questions
It can sit close to the boundary, but anything within 2m of it must be no more than 2.5m high overall under permitted development. Building Regulations also matter here: a room of 15m² to 30m² normally avoids approval only if it sits at least 1m from the boundary or is built substantially of non-combustible materials.
Not under permitted development. The use has to be incidental to the house, which rules out separate living accommodation and bedrooms. Sleeping accommodation also brings the building under Building Regulations whatever its size. If you want a guest room in the garden, it needs planning permission and building control approval from the start.
Often, yes, for some positions. In a conservation area, an outbuilding between a side wall of the house and the boundary needs planning permission, and other local restrictions can apply. Check with the council before designing it, and if the house is listed, any outbuilding in its grounds needs permission regardless of size.
Planning garden rooms work?
Send the address, a few photographs and what needs to change. We will tell you what applies to your property.