Juliet balconies, balconies and the overlooking test

A balcony on a house needs planning permission. There is no householder permitted development route to one, because Class A of the General Permitted Development Order 2015 excludes any work that consists of or includes the construction or provision of a verandah, balcony or raised platform. A Juliet balcony is different: a guarding across a set of French doors, with nothing outside the wall to stand on, is usually treated as an alteration rather than a balcony, and often falls within permitted development.

That distinction is the whole question for most householders. Where there is a floor you can stand on, you are applying for permission and the council will judge the scheme on overlooking.

Why a balcony is never permitted development

The exclusion sits in the limitations to Class A, and it is absolute. Size, position and materials make no difference. The same wording appears in the other householder classes, so you cannot reach a balcony through a roof alteration or an outbuilding either.

The Order also defines a raised platform as one more than 0.3 metres above the ground. A decked seating area 250mm above the lawn is therefore outside the exclusion, while the same deck built up to 400mm is caught by it. People discover this after the decking is down.

Because permitted development is a question of law rather than judgement, the only way to be certain is an application for a lawful development certificate under section 192 of the Town and Country Planning Act 1990. Councils charge half the householder fee for one, and a certificate is worth having when you sell.

Juliet balconies and where the line falls

A Juliet balcony is a guarding fixed to the face of the building, across doors that open inwards or that open onto nothing. Replacing a first-floor rear window with doors and a guard is an alteration to the dwellinghouse, and alterations are within Class A provided the other limits are met.

The line is physical. If the structure gives a person somewhere to stand outside the plane of the wall, it is a balcony. If the guard is flush or projects a few centimetres and there is no floor surface, it is not.

Two things still catch people out. A Juliet balcony in a side elevation at first floor is caught by the condition requiring upper-floor side windows to be obscure-glazed and non-opening below 1.7 metres, which a set of doors cannot satisfy. And on land where permitted development has been removed by an Article 4 direction, or on a listed building, the alteration needs an application regardless.

How councils measure overlooking

Overlooking is a material consideration, and officers assess it by looking at what a person standing on the balcony can see, not what the drawing shows. Expect three questions.

The first is the angle of view. A rear balcony that looks straight down a neighbour's garden at close range is harder to defend than one angled along your own plot. The second is the distance to the affected window or garden. The third is whether the view is already available from an existing window at the same level, because a balcony that adds no new line of sight is a weaker objection than it looks.

That last point is worth making in writing. If the first-floor bedroom window already looks over the same garden, the balcony changes the duration and the sense of being watched rather than the geometry, and officers do weigh those separately.

Gardens count. The private sitting-out area immediately behind a house carries more weight than the far end of a long garden, and a balcony aimed at a neighbour's patio is the version most likely to be refused.

Separation distances in local design guidance

Most councils publish a householder design guide with separation distances, usually a back-to-back figure between facing habitable room windows and a shorter figure to a blank wall or a garden boundary. The figures differ between authorities and the one that binds you is the one your council has adopted, so download the guide before drawing anything.

Distances in those guides are starting points rather than tests. An officer will depart from them where the levels, the boundary treatment or the orientation change the effect, in both directions. A balcony that meets the stated distance can still be refused where the land falls away and the platform sits above the neighbour's fence line.

Where levels vary, a cross-section through both properties at the same scale does more for the case than any amount of description.

Screening, obscure glazing and other fixes

Most refusals on overlooking could have been avoided with a screen. The usual solutions are a solid or obscure-glazed privacy screen to at least 1.7 metres above the balcony floor on the flank most exposed, planters set back from the edge to keep people away from the boundary, and a reduced depth that makes the platform usable for standing rather than sitting.

Offer the screen on the drawing. Officers can and do impose it as a condition, but a scheme that already shows it reads as considered, and there is no negotiation to have later about the material.

Obscure glazing to a fixed level, with any opening light above 1.7 metres, is the standard answer for a side-facing element. It is unpopular with clients and it is frequently the difference between approval and refusal.

Roof terraces over a rear extension

A flat roof on a single-storey rear extension looks like free outdoor space, and it always needs permission. It is a raised platform, so it sits outside Class A, and it puts people at first-floor level directly on the boundary of two gardens.

These applications succeed where the terrace is set well back from the rear wall, enclosed on both flanks by screens to head height, and limited in area so it reads as a small sitting-out space rather than a second garden. They fail where the terrace runs to the edge of the extension and looks over two gardens at once.

Where the property is in a conservation area, add the effect on the character of the rear roofscape to the assessment. Sensitive settings attract objections about clutter on the skyline as well as privacy.

Putting the case in the application

A householder balcony application is decided on drawings and one short written statement. The drawings should show the balcony in plan, elevation and section, with the screen heights marked, the finished floor level dimensioned, and at least one section cut through to the neighbouring boundary.

A short Planning Statement then does the arguing: the development plan amenity policy, the separation distance in the council's design guide against the distance you achieve, the existing views from existing windows, and the mitigation offered. Where a neighbouring window is close and habitable, a daylight and sunlight assessment covering the effect of the screens is proportionate. It also helps to check the boundary issues that come with corner plots and rear extensions near a side boundary, and to look at how upper-floor alterations are handled when adding a first floor within an existing roof.

Two things to avoid. Do not describe the balcony as a Juliet balcony on the form if it has a floor, because officers read drawings. And do not leave the screen off the drawings in the hope of adding it later, since a refusal costs eight weeks and a resubmission.

Draft the supporting statement for a householder application on PlanScope and send it to a planning professional to review before you submit.

This is general guidance, not legal advice. A lawful development certificate is the only formal way to confirm that works are lawful, so check the position with your local planning authority or a qualified professional before relying on it.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.