There is no fixed price for a steel balcony. It depends on the type, size, balustrade, decking, finish and how the structure fixes back into the building. A Juliet balcony guarding a door opening is a different job to a bolt-on cantilevered platform you walk out onto. This guide ranks the drivers that set the figure before you ask for a steel balcony quote.
The four balcony types compared
| Balcony type | How it is supported | What drives the price |
|---|---|---|
| Juliet balcony | Guards a full-height opening, no walk-out platform | Opening width, balustrade style, finish |
| Bolt-on cantilevered balcony | Fixed back with engineer-designed connections, no posts | Wall or floor capacity, projection, steel section size |
| Post-supported balcony | Columns to the ground carry the platform | Column count and height, foundations, decking |
| Walk-on terrace or roof balcony | Built into an existing flat roof or podium | Waterproofing detail, structural loading, drainage |
Structure and fixings: the biggest driver
What the existing wall or floor can take, and how the steel connects into it, is the single largest factor. A cantilever puts real force through a small connection point, so the fixing is sized to the substrate: masonry behaves differently to a timber frame. This is engineered work, where a structural engineer’s calculation and Building Control sign-off matter most. Our custom staircases and balconies work starts from this detail.
Size and projection
A wider opening or deeper projection needs heavier steel to span without excessive deflection, and on a cantilever a deeper platform multiplies the leverage on the fixing point. A small Juliet balcony over one door is among the least demanding jobs we build; a wide projecting terrace is among the most.
Balustrade type
Vertical steel bar is the most economical and common choice. Mesh infill sits close on price. A handrail-and-baluster design has more welded joints and takes longer to build. A glass balustrade, framed in steel, costs more again because toughened panels and their fixings are a separate specification, but it gives an unbroken view bar guarding cannot match.
Decking
A Juliet balcony skips decking entirely, but on anything you stand on it is a real cost line. Steel grating drains and ventilates itself. Timber on a steel frame gives a warmer finish but adds maintenance. Composite costs more up front and needs less upkeep. Glass decking is the most specialist and expensive, reserved for a genuine feature.
Finish
Hot-dip galvanising is the baseline for outdoor steel and gives strong corrosion resistance alone. Powder coating over galvanising adds a durable colour finish at extra cost. Paint without galvanising is the least durable option, one we steer you away from outdoors. Stainless steel is the premium route: no coating needed, but a higher material cost throughout.
Access and installation
A ground-floor balcony with clear access is straightforward. A first or second-floor balcony usually needs scaffold or a mobile elevating work platform (MEWP) to hold the steel while it is fixed and welded, and a larger cantilevered section on a restricted site can need a crane lift. Height and access shape the installation plan.
Planning and regulations
A projecting balcony changes external appearance and can affect neighbours’ privacy, so it usually needs planning permission on a house. A Juliet balcony is treated more leniently, though the door opening can still need consent, and flats, listed buildings and conservation areas differ again. We cannot give a planning ruling: confirm your specific project with your local planning authority. See planning permission for steel buildings for the wider picture and Juliet balcony building regulations for that route specifically.
What you can decide to bring the figure down
A Juliet balcony over a walk-out platform removes the platform, decking and load path entirely. Keeping the opening or projection to what you actually need, rather than oversizing it, keeps the steel section smaller. Vertical bar costs less than glass or a detailed handrail, and galvanising with powder coat is a durable, mid-cost finish rather than jumping straight to stainless. These are specification choices, not safety compromises.
What to send for a quote
Drawings or measurements of the opening, the balcony type, what the wall or floor is built from, your balustrade and decking preference, the finish, and site access. A short survey confirms the fixing detail against the real building. Alongside a staircase or handrail scope? See steel staircase cost, steel balustrades and handrails, and structural steel project timeline for how long a project like this typically takes.
T C Rowan is CE approved and works to BS EN 1090 execution standards, designing, fabricating and installing from our own Banbury workshop. Guarding heights and barrier loading are set out on the gov.uk Approved Document K page.
Get in touch for a free quote.
Frequently asked questions
How much does a steel balcony cost in the UK?
There is no single figure: a Juliet balcony with no walk-out platform is a different job to a bolt-on cantilevered balcony or a post-supported terrace, and within each type the wall or floor it fixes to, the size, the balustrade, the decking, the finish and the access all move the price. The only accurate figure is one priced against your drawings, which is why we quote every balcony individually rather than publishing a rate card.
Is a Juliet balcony cheaper than a walk-out balcony?
Generally, yes. A Juliet balcony guards an opening rather than carrying anyone’s weight, so the steel is lighter and the fixings simpler, with no platform, decking or floor loading to design for. A cantilevered or post-supported balcony carries live load and needs engineered, connected fixings, Building Control sign-off, and more steel. That gap is usually the single biggest factor in the final figure.
Do I need planning permission for a steel balcony?
It depends on the balcony and the property, and we are not able to give a planning ruling. Generally, a balcony that projects out and creates a new platform needs planning permission because it changes the building’s external appearance and can affect neighbours’ privacy, while a Juliet balcony usually does not, though the door or window opening it sits in can still need consent. Flats, listed buildings and conservation areas are often treated differently again. Always confirm your specific project with your local planning authority before committing to a design.
What information do you need to quote a steel balcony?
Drawings or clear measurements of the opening or elevation, the balcony type (Juliet, cantilevered, post-supported or walk-on terrace), what the wall or floor is built from, your balustrade and decking preference, the finish, and how we would access the site. A short site visit confirms the fixing detail and turns that into a firm number. Contact us and we will arrange a free, no-obligation quote.