Do you need planning permission for an outdoor sauna in the UK?

Permitted development

Four factors generally allow a sauna to be built without a planning application:

Height limits

Structures cannot exceed 4 metres with a dual-pitched roof, or 3 metres with any other roof type. Within 2 metres of a boundary, the maximum height drops to 2.5 metres.

Garden coverage

The sauna and any other outbuildings must not cover more than 50% of the garden area surrounding the original house.

Placement

Structures must sit behind the principal elevation of the house — not forward of the front wall.

Use

Permitted development is for private residential use only. Commercial use, holiday lets or guest accommodation typically triggers a change-of-use requirement.

When permission is required

A planning application is likely to be necessary where any of the following apply:

• The property is a listed building, or sits in a conservation area, national park, or Area of Outstanding Natural Beauty.
• The structure exceeds the permitted height limits.
• Outbuildings would cover more than 50% of the garden.
• The sauna serves a commercial purpose.
• Original planning conditions restrict permitted development rights.

Building regulations

Planning and building regulations are separate. As a general guide:

• Saunas under 15m² are usually exempt, provided there is no sleeping accommodation.
• Between 15–30m², compliance depends on proximity to a boundary.
• Over 30m² requires full compliance.
• Electrical work must comply with Part P regardless of the structure's size.

Scotland, Wales & Northern Ireland

Rules differ significantly outside England. Always consult your local authority before proceeding.

This guide is a general overview, not formal planning advice. Regulations change and every site is different — confirm the position with your local planning authority, and we'll help resolve it as part of the design.