Do you need planning permission for a balcony or roof terrace?

Development is not permitted by Class A if ... it would consist of or include (i) the construction or provision of a verandah, balcony or raised platform "raised" in relation to a platform means a platform with a height greater than 0.3 metres

What counts as what

The Order does not define the words, apart from "raised". The technical guidance does:

Garden decking no more than 0.3 metres high is a different matter: see decking and hot tubs.

Roof terraces

A terrace on the flat roof of an extension, a garage or a dormer is a raised platform, so it needs planning permission. A balcony or terrace cut into a main roof as part of a loft conversion is excluded from Class B as well (B.1(e)(i)), and a garden building under Class E cannot include one either (E.1(h)). The same applies to building a new extension with its roof designed as a terrace: the platform takes the whole extension outside Class A.

Juliet balconies

A Juliet balcony is an alteration to the house under Class A, so the Class A conditions still apply, including similar materials (A.3(a)) and the rule that upper-floor side windows are obscure-glazed and fixed below 1.7 metres (A.3(b)). In a dormer, it must also meet the Class B limits in loft conversions and dormers. Where an Article 4 direction has removed Class A rights for windows and doors, the new opening needs permission.

Flats, listed buildings and conservation areas

The exclusion is the same on Article 2(3) land, which includes conservation areas, as anywhere else. Flats have no Part 1 rights at all, so a balcony or terrace on a flat needs planning permission (flats and maisonettes). On a listed building, a Juliet balcony that affects its character needs listed building consent (section 7 of the Planning (Listed Buildings and Conservation Areas) Act 1990).

Building Regulations

The Planning Portal says Building Regulations apply to most external platforms: the structure, including any new opening in the wall, the height of the guarding, fire spread and security.

What this means for you

Plan on a planning application for any balcony or terrace. The Planning Portal points to neighbours' privacy and gardens as the things to consider in the design. Test the rest of your project in the permitted development checker.

Getting certainty

For a Juliet balcony, a lawful development certificate for proposed works confirms that it is permitted development: £274 from 1 April 2026, decided within 8 weeks. For a balcony or roof terrace, the certainty is a householder planning permission, £548 from the same date.