Yes, almost always. On a house, a walk-on balcony, a roof terrace or any raised platform over 0.3 m falls outside permitted development, so you need a planning application to Bromley Council, and on a flat you need one too. On a house, a Juliet balcony, which has no platform to step out onto, is normally the exception.
We make and fit steel balconies from our Bromley workshop, and we look at the planning position for your own address when we come to measure. Below is what balcony planning permission in Bromley costs from April 2026, how long it takes and what the council wants to see.
- What applying costs£548national fee, paid to the council, for one house or one flat, from April 2026
- How long8 weekslegal time limit for a decision once the application is valid, unless you agree more time
- What the council asks forPlans & photossite plan, floor plans, elevations and dated photos
What counts as a balcony for planning
The technical guidance the government publishes for householders calls a balcony a platform with a rail, balustrade or parapet sticking out from an upper storey. The national rules that let you extend a house without applying (the General Permitted Development Order 2015, Class A) leave out verandas, balconies and raised platforms.
A raised platform is any platform higher than 0.3 m, roof terraces included. So on a house, a deck off an upstairs bedroom, a balcony on posts and a flat roof turned into somewhere to sit all need an application.
Do Juliet balconies need planning permission?
A Juliet balcony is a guard rail fixed across an upstairs door opening, with no floor outside it. With no platform, the same guidance says it would normally be permitted development. But a listed house, a flat, or a home where one of Bromley's Article 4 directions has removed the relevant rights can be different.
Bromley's planning pages say officers can't advise informally on permitted development. If you want certainty, a Lawful Development Certificate (LDC) for proposed works gives you the answer in writing. It's optional and costs £274 from April 2026. For railing patterns and finishes, see our Juliet balconies page.
Balconies on flats and maisonettes
Flats get none of the householder permitted development rights: the government's definition of a house for those rules leaves out flats and any building containing them. A balcony on a flat needs a full planning application, and Bromley's householder checklist points flat owners to its Full Planning checklist instead.
Leaseholders should also check the lease: it can require the freeholder's permission for alterations, quite apart from planning.
Balcony planning permission in Bromley: what the council looks at
Bromley aims to decide 90 per cent of applications under delegated powers, which means a planning officer rather than a committee. Officers test a balcony against the Bromley Local Plan (2019) and the council's design guidance, and three points stand out.
- Your neighbours' privacy. Policy 37 expects new work to respect the people next door, so they don't lose privacy, daylight or sunlight. The Planning Portal's balcony advice makes the same point.
- Fit with the house. Policy 6 asks that an extension's scale, form and materials respect or complement the existing house.
- The railing. Bromley's Urban Design Guide (July 2023) is written mainly for new developments, but it shows how the borough sees balconies. It wants metal balustrades finely detailed and matched to the building, and says glass can look generic in a traditional suburban street, so it won't be accepted in most cases.
For overlooking, the same guide suggests perforated patterned metal balustrades, or balustrades that are part solid and part open at the front and side ends. That matches our own drawings: a modest depth, a slim steel frame and a screen on the side facing the neighbours.
Having built balconies around Bromley, Beckenham and Chislehurst, we draw with those points in mind from the start, though nobody can promise a planning decision. More on our steel balconies.
Conservation areas, listed homes and special character areas
Bromley has 47 conservation areas, and the council's conservation areas page links to a map showing whether your home is listed, locally listed or inside one. The Planning Portal notes that listing or conservation-area status may have a bearing on the decision.
Areas of Special Residential Character, such as Petts Wood and Park Langley, have their own policy (44) asking new work to respect what makes them distinctive. On a listed house you will almost always need listed building consent as well; Bromley's listed buildings page warns that altering one without it is an offence.
What the application costs
- Planning application: £548 for a single house from 1 April 2026, and the same for a full application on one flat. The fee is set nationally, paid to the council and updated every April.
- Lawful Development Certificate: £274 for proposed works on a house, half the full fee.
- Bromley pre-application advice: £250 for a householder proposal, or £720 for work to a listed home. Both are written advice with no meeting, VAT included.
- Listed building consent: no fee.
- Drawings: order your balcony from us and our elevation and plan drawings for the application cost nothing extra.
The Planning Portal adds its own service charge to some online applications with a fee over £100. The balcony itself is priced after a free survey, as a fixed quote in writing.
Thinking about a balcony in Bromley?
Ring the workshop, or use the form and attach a picture of the house from the garden side. Our drawing can go with your application.
How long it takes
- Checking the paperwork. Bromley aims to validate within 3 to 5 working days, though it can take longer when the team is busy. If something is missing, the application is held for 21 days, then withdrawn.
- Neighbours. The council writes to the adjoining neighbours, who get at least 21 days to comment.
- The decision. The legal time limit for an application like this is 8 weeks, unless you and the council agree a longer period in writing.
- Making and fitting. Once our drawing has your approval, the balcony is welded, zinc-dipped and powder coated, which takes a few weeks. Fitting is a day for most balconies.
We wouldn't add those up and promise you a date: the council's clock only starts once the application is valid.
What the council will ask for
Bromley's householder validation checklist asks for a site location plan edged in red, existing and proposed floor plans with the width, height and depth marked, elevations and site photos. Its validation guidance adds that the photos must be up to date and date-stamped. If the work encroaches onto a neighbour's boundary, you need Certificate B.
Get the drawings right first. Once an application is valid, Bromley says it generally can't negotiate or meet to discuss it, and it won't take revised plans unless the planning team has agreed that in advance. So pre-application advice is the time to test a design.
Bromley says the easiest way to apply is through the Planning Portal, and its planning applications search lets you look up past applications and decisions on nearby houses.
That is where our free survey helps. We visit within days of your call, and within a week you get a scaled CAD drawing and a fixed written quote. You can use that drawing for planning, and the sooner it is done, the sooner your application can go in. Ring 07828 730 888 or send us the form.
Building regulations are a separate check
Planning decides whether you can have a balcony; building regulations decide whether it is safe. The Planning Portal says they apply to most external platforms, covering structure, guarding and fire safety. Diagram 3.1 of Approved Document K sets a minimum of 1100 mm for the guarding on a single-family house's external balconies, and that covers Juliet balconies too.
For balconies on flats, the diagram gives the same 1100 mm. We design our balconies to Approved Document K, with BS 6180 for the barriers, and at the end you receive our drawings plus a certificate of conformity. Our survey and drawing service explains each step.
Planning a balcony? Ring 07828 730 888, or fill in the quote form at the foot of this page with a photo of where the balcony would go, if you have one. There's no charge and no obligation for the survey, and the drawing that follows can go in with your planning application. More on our local work: external staircases and balconies in Bromley. Or book your survey from the contact page.
Quick questions
Can I add a balcony to my flat without planning permission?
No. Householder permitted development stops at houses, so a flat needs a full planning application (£548 from April 2026), and a leaseholder may need the freeholder's consent too.
Is a roof terrace treated like a balcony?
Yes. Any platform higher than 0.3 m counts as a raised platform, roof terraces included, so on a house it needs planning permission. For a single-family house, Approved Document K's Diagram 3.1 sets at least 1100 mm of guarding along roof edges people can get to.
What happens if you build a balcony without permission?
You can apply afterwards with a retrospective application. But if the work needed permission and you went ahead without it, the council can serve an enforcement notice ordering you to undo the changes, and ignoring one is illegal unless you win an appeal.