There have been recent cases noted in the newspaper, or on the news, of people suffering injuries from collapsing balconies. This can occur for many reasons.
The Building Code of Australia requires that handrails be installed where the height of a balcony, deck, landing or stairwell is more than 1.0 metres from the adjoining ground level. This can also apply where there are raised ground levels within a property and a sheer rock face or similar is evident.
The previous Standards of the Building Code requirements allowed for a handrail to a height of 825mm. This was found to be inadequate as for some people it is well below waist height and can allow a person to fall and suffer substantial injuries from those balconies. The height has now been increased to 1.0 metres for most balconies, but for some high rise units the height above patio is higher. Many units are now replacing handrails to meet the current height requirements to reduce the risk of injuries, as well as litigation. Where the Owner’s Corporation do not replace the handrails as part of their risk management, they are exposed to litigation.
Current and previous Standards allow for glass handrails to be installed. In some idyllic locations, vertical toughened glass can be installed and set within the concrete slab. It has been found that toughened glass can shatter, which would leave that balcony with a substantial hole which can result in a person falling from a multi-storey building. Recent amendments to the Australian Standard for glass handrails has required that a metal capping, or handrail, be provided on or at the top edge. The reasoning is that should one (1) glass panel shatter, then the remainder of the adjoining panels can provide some restraint and prevent a person from falling.
Cantilevered external balconies, which are common on many units, can result in some minor sag due to the weight of the brick handrails. Whilst in the majority of cases this is not an issue, it can be of a concern with older buildings in beachside locations. The sag to the balcony slab may result in fine cracking where the balcony abuts the main building and a salt laden environment can cause deterioration of the steel reinforcing within the concrete. There can also be under designed or inadequately built balconies which can also result in excessive deflections. Whilst there have been very few cases of collapsed balconies, this can occur particularly if a large gathering or persons, such as a party is held on a weakened balcony.
The main concern with collapsing balconies is rot and deterioration to external timber decks.
Timbers come in various durability grades and this is extremely important as many of the timbers used are a low durability grade in an external application.
As the following photographs show, attempts can be made to provide additional stabilisation to the deck, however should rot commence in the structural timbers then the structural framework is compromised and the timbers are at risk of collapse.
In some cases temporary propping is installed, however generally this is inadequate.
Further the decking boards are likely to be subject rot and deterioration due to exposure over a prolonged period of time.
It is usual practice when rot and deterioration commences, the balconies then have a limited lifespan, are structural inadequate and require replacement.
A recent phenomena that has been seen is the use of structural grade pine timbers for floor joists in enclosed balconies. Whilst this may be suitable, the entire structural adequacy and design life of the balconies is subject to the adequacy of the waterproof membranes. There have been recent cases where external timber frame and tiled balconies have collapsed due to water ingress. The water ingress can occur where bolt fixing for handrails extend through the tiles and membrane and allows water to track into the structural timbers resulting in virtual collapse of the balcony over a 3-5 year period. Also should the membrane be inadequate, or is affected by timber shrinkage, then rot will occur.
The above balcony was deflected due to rot in the main support beam, as shown in the right hand side photograph and the photo below.
The above photographs illustrate the requirements that a suitable grade durability timber be used in all external balconies, including for tiled balconies.