How to Specify a Balcony

How to Specify a Balcony

Aa an integral part of a building façade, balconies should be designed and specified during the early stages of a project to ensure excellent aesthetic appeal and avoid potentially costly problems further down the line. That’s the advice of Nick Haughton, Head of Marketing at Sapphire Balustrades, who offers this step-by-step guide to help specify a balcony solution for your development.

As well as providing additional floor space, balconies can add the ‘wow-factor’ to a residential development and help boost sales appeal, especially if the balcony offers views of a park, water or striking urban skyline. Whether it’s a Juliet (Juliette) or a walk-on structure, a balcony is a key design element of a building’s external architecture and as such can be designed and manufactured to complement or contrast the style of the development and the materials used in the façade, including render colour or cladding panels.

The choice of balcony systems is critical to achieving the desired aesthetic and functional specification. However, whilst getting the right look is clearly important, selecting the type of balcony for a particular project may also be influenced by factors such as planning, space or budget restrictions.

Start with the aesthetics of a balcony, using free tools like CABS to create instant and easy visual representations  and once you know what is needed work back from their seeing how the integration can be simple and balconies.

Let’s take a closer look at the main types of balcony and some of the key design and technical considerations, from the support structure and connection details to cold bridging.

Firstly, the Juliet balcony, which is essentially a balustrade around a window or door opening but still an effective way of bringing an open, outdoor feel to an indoor space when a projecting balcony isn’t practical.  To specify Juliette balconies only is not very common in the highrise residential world, as in the main they are specified along with cantilever balconies.

Next, the Integrated balcony, which as the name suggests is part of the structural façade, rather than being bolted on to it. Basically speaking, the building’s concrete frame forms a projecting platform. Such applications are often used on roof terraces where, for example, the penthouse is set back from the rest of the building edge, but in the main end up much more expensive and difficult to achieve than metal balconies.

Where a balcony is to protrude from the building using a metal balcony frame, perhaps the biggest design challenge is the support structure. Balcony decks can be self-supporting, whereby legs or columns take the weight of the balcony, or more commonly the balcony is bolted on to the building, creating a cantilever deck. With the latter option, the balcony is supported in some way by the existing building structure and there are no visible supports apart from the fixing to the face of the building. Needless to say, this type of balcony will impose greater fixing loads on the building frame. It is, therefore, essential to agree the balcony design and fixing requirements at an early stage of the project to accommodate this. Thermal conductivity should be another consideration when specifying fixings for a cantilever balcony; whether using a steel-framed system or cast-in fixings (for example Schoeck Brackets) in a concrete frame. The balcony connection points can cause a cold bridge from the cold balcony to the warm inside, so a thermal break must be specified to reduce the risk of condensation forming at cold points inside the building.

As part of an ongoing development programme, Sapphire has been exploring new ways to address some of the technical design issues associated with add-on balconies. These include innovative connectors for faster, simpler fixing to façades and offsite manufacturing of complete balconies, which are delivered to site ready to be fixed to the façade, saving significant on-site time and cost of external access scaffolding. We’ve also added an Ultra-Slim steel-framed system to our bolt-on balcony range, which enables very slim balcony profiles as the balustrade fixing and balcony frame are integrated into one.

This brings us to the subject of balustrades because every balcony needs to be enclosed to be safe and guard from potential accidents. As well as ensuring the safety of those using the balcony, balustrades play an important aesthetic role. Glass is widely used for balcony balustrades as it provides the perfect balance of light, visibility, and safety, whilst being very low maintenance. An extensive choice of glass thicknesses and types is available to specify, including tinted and self-cleaning. Perhaps surprisingly, glass infill panels for balcony balustrades are often a more cost-effective solution than mesh or vertical bars, for example, whilst having a higher perceived value, which is critical for maximising a property development’s return on investment. And from our experience at Sapphire, curved glass can be used to stunning effect around larger balconies or roof terraces.

Corrosion is one of the most common problems with any external balustrade and it’s not just an aesthetic consideration as rust can impair structural integrity. To overcome this Sapphire uses aluminium or 316 marine grade stainless steel for handrails and uprights in its balcony balustrade systems. In fact, all our components, whether fully exposed or completely concealed, are designed to be corrosion-resistant. Our advice is to beware of using mild steel, even if galvanized, or the using of the wrong grade of stainless steel for external balcony balustrades. Using a polished 304 grade stainless steel may seem a reasonable solution, however it will show corrosion and unsightly staining over time, so externally we would always recommend a 316 grade stainless steel. Alternatively, aluminium offers a guaranteed rust-free solution for balcony balustrades and is a cost-effective alternative to mild steel, both at initial investment and over the building’s lifetime. An anodised or powder coated finish can be specified, and by opting for the latter the balcony balustrades can be produced to match features such as window frames and doors to create a co-ordinated look to the façade.

So to sum up, balcony design and what a designer chooses to specify shouldn’t be left to chance. Working with an experienced balcony manufacturer to specify an intelligent approach from an early stage of a project can allow ‘true’ value engineering such as optimum offsite fabrication and best fixing method to save on-site time.

…and the free tool

As we said, start with the aesthetics and let experience drive the specification. Both are available in the free CABS tool which gives a simple way of playing around with the balcony you want whilst automating the specification and report. Try it here