The questions we get asked most often about steel walk-out balconies, answered properly rather than in sales language. If yours is not here, call 0114 243 9009 or email sales@diomet.co.uk.
What is a walk-out balcony?
A structural platform you can walk out onto and stand on, carried on a steel frame fixed to the building and, where needed, posts down to the ground. It is not the same thing as a Juliet balcony, which is a barrier across a door or window with nothing to stand on, or a step-out balcony, which gives you a shallow platform on gallows brackets with no posts.
What is it made from?
A steel ring beam and support posts, steel joists inside the frame, composite decking on top, and a balustrade of your choice: metal railings, framed glass, or frameless glass.
We use steel joists rather than timber ones. Most balconies of this type are built with a steel frame and timber joists inside it, which is cheaper and looks identical on day one. The difference shows at the wall junction, where a timber joist end sits in the damp behind the fascia and nobody ever inspects it. It also shows from underneath, which on a balcony over a doorway is a view you get every time you walk in.
How is it finished?
Hot dip galvanised first, then powdercoated, in that order. The galvanising is the corrosion protection and the powder coat is the colour, so a chip is cosmetic rather than the start of a rust problem. Powder coat on bare steel looks the same for the first few years and is a maintenance job after that.
Any RAL colour, at no extra cost over the standard finish. Anthracite grey (RAL 7016) and black are the most common, but matching the balcony to your window frames is often the better looking answer. There is an example of that on our brown powdercoated balcony in St Neots.
Galvanising and powder coating are done by specialist plants rather than in our own workshop. Everything else, the design, cutting, welding and fit-up, is done by us in Sheffield.
Is it compliant with building regulations?
The balcony is designed to meet the current UK requirements for a domestic balcony: 1100mm guarding above finished floor level, no gap that will pass a 100mm sphere, and the 0.74 kN/m external domestic barrier load from BS 6180. The steelwork is fabricated to BS EN 1090-2 and UKCA marked, and a Declaration of Performance is issued with it.
What we cannot do is sign off your building. Whether your wall, your foundations and your particular situation satisfy building control is a matter for your building control officer. Our balcony and Juliet balcony building regulations guide sets out the figures in full, and the UKCA certification page explains what the marking covers and what it does not.
Do I need planning permission?
Almost certainly, yes. Balconies, verandas and raised platforms sit outside permitted development, so a householder application is normally part of the job. It is also usually the longest part of the programme: manufacture is measured in weeks, a householder application has an eight week statutory target and can run longer.
Overlooking is the objection that actually comes up, which is why a privacy screen on the neighbour facing side is often either a planning condition or cheap insurance against one. We can supply a general arrangement drawing for the application, charged separately and deducted from the order if the balcony goes ahead.
Two things are exempt: a Juliet balcony with no platform, and a raised platform under 0.3 metres.
Where the rest of our range stands, and the overrides that cancel permitted development entirely for flats, listed buildings and Article 4 areas, is set out in do I need planning permission?
How big can it be?
Width is effectively unlimited, it simply needs more posts as it gets longer, though with only two front posts six metres is a sensible maximum. Projection is up to three metres on our standard steel joists. Beyond that the joist section grows considerably and it becomes a much heavier and more expensive structure.
Sizes on the product pages are price bands rather than fixed sizes. You pick the band your opening falls into, the balcony is made to your exact dimensions, and awkward sizes get a drawing for approval before anything is cut.
Does it have to have posts?
On an existing house, usually yes, and that is not a compromise. A true cantilever puts the entire overturning moment into the wall it is fixed to, which on a cavity wall means resolving fixings through to the inner leaf with a structural opinion behind it. Posts take the load to pad foundations, reduce the wall connection to a restraint, and leave the space underneath usable and covered.
Where posts genuinely are not wanted, the realistic answer is a step-out balcony on gallows brackets, up to 2400 x 1200mm.
Put plainly, there are three ways a balcony stays up, and each suits a different situation:
- Support posts. The most popular design for a house, and the easiest to retrofit. The posts go onto pad foundations or precast slabs, the wall connection becomes a restraint rather than a structural fixing, and the area can be as large as you want within reason.
- Cantilever. The structure is counter-balanced inside the building, which is why you see it on new apartment blocks and almost never on a retrofit. The depth is limited by the steel member doing the balancing, and it has to be designed in while the building is being built.
- Gallows brackets, with or without a tie rod. Brackets carry the platform off the wall and leave the ground underneath completely clear, which suits a balcony directly above patio doors. A tie rod running back up to the wall above lets the bracket work harder. It is best on modest openings and shallow depths; push it too far and the brackets become the thing you look at.
Our retrofit guide goes through which of these your building can actually take.
Can I have a glass floor instead of decking?
Yes, as a full glass floor or a glass panel or two set into a solid deck. It is 33mm toughened and laminated glass with painted borders and a non-slip treatment, and it is priced per square metre of glass on top of the standard balcony.
We would usually steer you towards a partial glass floor. Floor glass does not like concentrated point loads, so chair and table legs are not ideal on it and dragging furniture about will eventually mark the surface. A partial floor gives you the light and the effect while leaving an area you can actually furnish. There is a full glass floor example on our balcony in Whissendine, Rutland.
If furniture is going out there anyway, spreader plates under the legs turn each point load into a distributed one, and soft neoprene rubber between the plate and the glass stops the surface being scratched. Keep the legs off the edges, where glass is at its weakest, and lift rather than drag. Our walk-on glass floor buying guide sets out what we will and will not advise on.
What is included in the price?
The design drawing service, the steel structure, the balustrade, the steel joists, the composite decking and the assembly fixings. Structural calculations, glass flooring, alternative balustrades, privacy screens, guttering, an adjoining staircase and delivery are priced separately.
What about the rain coming through the deck?
A standard open-joist balcony drains between the boards, so what lands on the deck ends up on whatever is below it. If you want to keep using the space underneath, we build in under-slung steel drainage trays with a gutter along the front edge, set with a fall in the workshop. It has to be designed in rather than added later, so say so at the quotation stage. See the balcony with integrated guttering in Pitlochry.
How long does it take?
Typically six to eight weeks from order. Delivery is quoted against your postcode and access once the size is known, rather than included in the online price. Collection from our Sheffield workshop is welcome if you would rather save the carriage. Our delivery and installation page covers how larger items arrive.
Can I fit it myself?
Many people do. Kits arrive part assembled with every hole pre-drilled, so there is no site fabrication, and installation drawings come with them. What you need is a competent installer, the right lifting help and properly erected access equipment. We are on the end of the phone while you do it.
We also install, with our own fitters rather than subcontractors, anywhere in the UK. Two DIY examples: Marlborough, Wiltshire and Cambridge.
How much maintenance does it need?
Very little. Composite decking does not rot, splinter or need oiling, and washes down with a brush. Galvanised and powdercoated steel wants an occasional wash and nothing else. External stainless on the balustrade is 316 grade, which is the one that does not tea stain outdoors. Our product maintenance page has the detail.
Is there a warranty?
Ten years on the balcony, free, set out in the warranty section of our terms and conditions.