Planning
Do garden rooms need building regulations approval?
Under 15 square metres is normally exempt. Between 15 and 30 it is exempt only if it is 1 metre from a boundary or non-combustible. Sleeping always needs approval; electrics always need Part P.
In short
Building regulations are separate from planning permission, and they catch garden rooms by size and use. A detached garden room with a floor area under 15 square metres and no sleeping accommodation is normally exempt. Between 15 and 30 square metres it is normally exempt only if it has no sleeping accommodation and is either at least 1 metre from any boundary or built substantially of non-combustible materials. Any garden room used for sleeping needs approval whatever its size. And regardless of size, the electrical work must comply with Part P, and any plumbing must meet the standards.
The thresholds
Where the line sits
Planning permission and building regulations are two separate things, and a garden room can need one, both or neither. Planning is about whether you can build it; building regulations are about how it is built. The trigger for building regulations is mostly size and use. Under 1
| Conditions | Floor area | Building regs |
|---|---|---|
| No sleeping accommodation | Under 15m2 | Normally exempt |
| No sleeping, and 1m from a boundary or non-combustible build | 15 to 30m2 | Exempt if conditions met |
| Regardless of use | Over 30m2 | Approval needed |
| Contains sleeping accommodation | Any size, for sleeping | Approval needed |
Source: Gardenscape. Figures as of 2026-06-01.
Yes, no, or it depends
Scenarios in plain language
Between 15 and 30 square metres, sitting within a metre of a boundary means it normally needs to be built substantially of non-combustible materials to stay exempt, otherwise it needs approval. We design around this.
Yes. Electrical work in a garden room must comply with Part P of the building regulations and be certified, regardless of the size of the room.
No, they are separate. A room can be permitted development for planning and still need building regulations, or the other way round. We handle both.
The local layer
Designated land and Article 4
Planning permission and building regulations are two separate things, and a garden room can need one, both or neither. Planning is about whether you can build it; building regulations are about how it is built. The trigger for building regulations is mostly size and use. Under 15 square metres with no sleeping accommodation, a detached room is normally exempt, with no restriction on how close it sits to a boundary. Between 15 and 30 square metres it stays exempt only if it has no sleeping accommodation and is either at least a metre from any boundary or built substantially of non-combustible
A note
General guidance, not advice. Rules vary by site, and Article 4 directions or conditions can change what applies. Check with your local authority and the Planning Portal.
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