Sponsored by Sapphire Balconies
In the bolt-on balcony business, bounce is bad. The surest way for property developers, their contractors and sales teams to avoid complaints from apartment dwellers is to insist that balconies are safe and comply fully with responsible manufacturers’ installation guidelines – and, naturally, all relevant building regulations.
Balcony bounce is unpleasant at any height – so much so that if an installed balcony is less than rigid, it should be regarded as a ‘fail’. If a bounce is detected, the cause is most likely because the installation does not comply with the manufacturer’s specifications. However, determining responsibility in a non-rigid situation can be difficult.
Leading producer Sapphire Balconies goes all-out to avoid bounce by manufacturing both the balconies and components necessary for a safe, durable installation. It backs this with the Sapphire Product Passport, proving rigorous processes to ensure the quality of manufacture and installation – taking responsibility for the whole process as ‘a safe pair of hands’ to work with.
Out of sight beneath these balconies is a cleverly engineered suspension system that combines life-long ‘no bounce’ rigidity with excellent thermal performance and ease of installation. It’s a key benefit that comes with the right choice of offsite-manufactured balconies that are simply craned into position, slid onto steel support arms and securely bolted into place.
The unseen ‘magic’ behind rigid balconies begins with a sturdy steel anchor that is cast into the reinforced concrete structure, inside the building envelope. With the addition of a thermal break and optional firestop, galvanised steel I-beams are bolted to the anchors – either as full arms or short stubs (to which arms are subsequently bolted) that protrude from the building façade.
It may be tempting for building specifiers to attempt to cut component costs by splitting an order between two or more suppliers – but the implications of any resulting ‘non-rigid’ problem could have far-reaching consequences in terms of legal argument and slow sales. For example, in a non-rigid situation with balconies and supports from different sources, where does the responsibility lie?
Sapphire regards the visible balcony and the concealed supports as a single system. Balconies are fully finished while anchors and stubs/arms are ready for casting into concrete slabs. This ‘buck stops here’ philosophy shows a willingness to accept responsibility for the whole balcony process and demonstrates the company’s ‘safe pair of hands’ competence.
With many thousands of factory-built balconies already adding value to medium- and high-rise apartment buildings nationwide, it’s worth considering the basic principles of installing the balconies and the major considerations for success.
This is the most common practice, but other solutions are available to suit alternative structural methods.
The choice of arms or stubs depends on various site conditions – including other trades’ activities on the exterior of the building, especially where mast climbers are deployed.
In the past, bolt-on balconies were simply attached to stubs, but with the growing popularity of today’s rigid balconies – especially on large-scale developments – there was demand for a faster and safer installation method. The solution was the glide-on cassette balcony, factory-built to tight specifications and delivered to the site ready for craning into position and anchoring to the protruding arms.
Generally, one-piece arms are more efficient, more cost-effective and slightly more rigid than the stub-arm combination. The rigidity of a balcony on one-piece arms is enhanced as there are fewer joints – but it’s unlikely that any difference in rigidity would be noticeable to the typical end-user. Either way, the structural performance and durability of these components are vital for a good balcony, and they must comply with BS EN 1090 marking requirements.
One-piece arms enhance rigidity as there are fewer joints. They also reduce time and costs as there are no additional sections to manufacture or install. Arms and anchors can be factory-assembled to facilitate casting in complete pieces.
On the other hand, stubs allow easier mast climber access and may be used as tie points during construction – avoiding further facade penetrations and the need for infill work when masts are dismantled. Stubs also avoid complications with scaffolding or formwork.
If a building does not have a reinforced concrete frame, various other balcony connection systems are available – all designed to outperform L/180 structural requirements. They include thermal breaks and the option to use either arms or stub/arm combinations.
There is comprehensive information available to assist architects and engineers in designing balconies that truly complement the apartment lifestyle. Getting the design and construction right in all respects will ensure rigid balconies. If it’s not right, balconies could feel ‘bouncy’, be subject to corrosion, have a negative impact on thermal performance – and in extreme cases even become a safety risk.
To learn more about Sapphire Balconies, visit their website: https://balconies.global/