Juliet balconies against full balconies in Class A terms

A Juliet balcony usually needs no planning permission. A balcony you can stand on always does. The difference is one line in Class A of the General Permitted Development Order, which does not permit development that consists of or includes the construction or provision of a veranda, balcony or raised platform. Guarding across a first-floor opening, flush with the wall, provides none of those things. A projecting or inset platform provides all of them.

That is the whole distinction, and it turns on whether there is somewhere outside the wall plane to put your feet.

Why balconies are excluded from Class A

Class A of Part 1 of Schedule 2 permits the enlargement, improvement or other alteration of a dwellinghouse, subject to a list of limits. One of those limits removes verandas, balconies and raised platforms from the right altogether.

The reason is overlooking. A first-floor standing area changes the relationship between a house and its neighbours in a way that a window does not, because a person on a balcony looks down and across at leisure, and can do so from a position outside the building. Parliament took the view that this should always be judged case by case, and the same exclusion appears in Class E for outbuildings.

So a rear balcony on a house, however modest, is a planning application. Roof terraces are the same problem in a different form, because the flat roof of a rear extension used as a standing area is a raised platform.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it, and remember that a lawful development certificate for proposed works under section 192 of the Town and Country Planning Act 1990 is the only formal way to confirm that works are lawful.

What a Juliet balcony actually is

A Juliet balcony is guarding and nothing else. Full-height doors or a floor-level window open inwards onto a barrier fixed across the opening, set in the plane of the external wall or immediately behind it. There is no floor outside, no projection and no area to occupy.

Its purpose is to let a first-floor room have a full-height opening for light, air and view without the fall risk. The room behind gains most of the daylight and outlook a balcony would offer, and the neighbours lose nothing they would not lose from a large window.

Two variants cause confusion. Guarding fixed to the outside face of the wall, projecting 100 mm or so with a decorative bracket, is still a Juliet because the projection is not occupiable. Guarding set forward of the wall with the floor extended out to meet it, even by 300 mm, is a balcony.

Whether guarding alone creates a balcony

The test officers and inspectors apply is function rather than appearance. Does the arrangement create an external area that a person can stand or sit on, outside the envelope of the building.

Four features that keep an arrangement on the Juliet side of the line.

• The internal finished floor extends no further than the internal face of the external wall.
• The doors open inwards, so the leaf does not sweep an external platform.
• The guarding is fixed in or immediately behind the plane of the wall, with no threshold step out.
• The opening has no external upstand, decking, tiling or drainage that would only make sense if the area were to be used.

Where the design creates any usable width, the honest answer is that it is a balcony, and describing it as a Juliet on the drawings will not survive an officer's site visit. That matters because a permission obtained on a misdescription is vulnerable, and because building it as permitted development invites enforcement.

The 0.3 m raised platform definition

The Order defines "raised", in relation to a platform, as having a height greater than 0.3 m. That definition does real work at ground level.

A rear terrace laid at 200 mm above the garden is not a raised platform and can be permitted development. The same terrace at 400 mm is, and needs permission. On a sloping plot the height varies across the deck, so measure at the highest point.

This is where garden decking schemes come unstuck. A deck stepping down from a rear extension threshold, sitting 500 mm above the lawn at the far corner, is a raised platform even though it feels like part of the garden. So is a platform on top of a single-storey extension roof, whatever the guarding around it looks like.

At first-floor level the 0.3 m figure is irrelevant, because any platform is a balcony, and the balcony exclusion applies whatever the height.

Overlooking, and how each type is assessed

For a Juliet, the assessment is the same as for any first-floor window. Councils look at the separation distance to facing habitable room windows and to the neighbouring boundary, the angle of view, and whether the opening is in a rear, side or front elevation. Many adopted design guides use a figure of around 21 m between directly facing habitable room windows, with a shorter distance to a boundary, and the figures vary between authorities so read the guide for yours.

For a full balcony the assessment goes further, because the user occupies the space rather than passing a window.

Officers look at the depth of the balcony, which controls how long people linger and how far forward they can lean. The position relative to the boundary, since a balcony at the rear of a terrace looks along the whole row of gardens. Whether privacy screens to the sides are proposed, their height and whether they are obscure rather than perforated. And the extent to which the balcony is recessed into the building, because an inset balcony within the footprint overlooks far less than a projecting one.

Two mitigations that are commonly accepted. Setting the balcony back behind the rear building line so the flank walls do the screening. And fixed obscure screens to both sides at 1.7 m or more above the balcony floor, secured by condition so they cannot be removed later.

A side-facing opening at first floor, whether it has Juliet guarding or not, will normally need to be obscure-glazed and non-opening below 1.7 m above the floor, which is a standing condition on Class A and a common condition on full permissions. How councils police it is set out under obscure glazing conditions and how they are enforced.

Guarding under the Building Regulations

Planning and Building Regulations reach the same opening with different questions, and the Building Regulations apply to a Juliet even where no planning permission is needed.

Approved Document K requires guarding wherever there is a drop of more than 600 mm. For a single family dwelling the barrier height is 1,100 mm above the floor for an external balcony, including Juliet guarding, and for a roof edge, with 900 mm applying to internal floors, stairs and landings. Where glass forms the barrier it has to provide containment as well as resisting the design loading, which in practice means laminated glass and a fixing designed for the purpose.

There are two further practical points. A window with a cill below 800 mm needs guarding in any case, which is why full-height glazing at first floor triggers the requirement whether or not anyone calls it a Juliet. And the opening usually still has to satisfy the escape window requirements for the room, which the guarding must not obstruct.

Drawing the distinction on the elevation

Most disputes come from ambiguous drawings, so make the distinction explicit rather than leaving the officer to infer it.

Include a section through the opening at a scale of 1:20, showing the internal finished floor level stopping at the internal face of the wall, the guarding position, and the absence of any external deck or threshold. Annotate it: guarding to the opening, no external standing area, doors opening inwards. Show the guarding on the elevation with its height dimensioned from the internal floor level.

Where the house is listed or in a conservation area, the design of the guarding becomes a heritage question as well. A galvanised steel balustrade on a Georgian rear elevation will attract comment, and a heritage statement explaining the significance of the elevation and the reversibility of the fixing is what carries the argument.

If you are applying for a full balcony, a short planning statement covering separation distances, the adopted design guidance, the screening proposed and the comparison with existing overlooking will do more than an extra drawing. And check what allowance the house has left first, since the position for a house that has already been extended is covered under extending a house that has already been extended.

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