Do you need planning permission for a catio? UK rules explained

Updated 6 November 2026 · By the Cat Enclosures team

Short answer: In England, most freestanding catios in back gardens do not need planning permission because they fall under permitted development for outbuildings, provided they are behind the front of the house, no more than 2.5 metres high within 2 metres of a boundary, and cover no more than half the garden with other outbuildings. Flats, listed buildings and some conservation areas have stricter rules, and catios attached to the house may be treated as extensions.

Permitted development limits for outbuildings in England

Not forward of the principal elevation, usually the front of the house
Maximum 2.5 m high if within 2 m of a boundary
Otherwise maximum 4 m for a dual-pitched roof or 3 m for other roofs, with eaves no higher than 2.5 m
Outbuildings together cover no more than half the land around the original house
No raised platform more than 30 cm high

When you may need permission or consent

You live in a flat or maisonette, which do not have the same permitted development rights
The property is listed, which needs listed building consent for many changes
The property is in a conservation area or national park and the enclosure is at the side
Permitted development rights have been removed by the council
You rent or are a leaseholder and need your landlord's or freeholder's consent

Fences and toppers

Fences and walls are normally permitted up to 2 metres, or 1 metre next to a road used by vehicles. A cat-proof topper that takes a fence above this may technically need planning permission, so keep heights in mind and speak to neighbours about shared fences.

Scotland, Wales and Northern Ireland

The rules are similar in principle but differ in detail. Check your local council's guidance or ask for a free informal opinion before building anything large.