In Queensland there are strict requirements when it comes to balustrades
Where a deck or balcony is one meter or higher above the ground then balustrades are required to be at least one meter high.
The openings in balustrades cannot be greater than 125mm.
If a deck is more than four meters above the ground, balustrades cannot have elements located between 150mm and 76omm from the floor.
Balustrades must be constructed so they can resist forces that can reasonably expected to be placed upon them, including people leaning against them and strong winds.
Retaining walls do not require a balustrade unless they are associated with a path of travel to and from or between buildings, however it is still a good idea to provide a balustrade or barrier where there is a risk of people falling.
Balustrades are required on stairs and are just as important as they are used as support for people ascending and descending the stairs. For stairs, a barrier of at least 865mm high above the nosing of the stair treads is required. For stairs more than 4m in height, a railing must also not have any climbable elements such as horizontal rails located between 150mm and 760mm from the floor.
Repair or Replacement of a Balustrade
You are only required to comply with the standard that the dwelling/building was constructed to, in relation to repair or replacement of the balustrade; however if the replacement is part of a substantial renovation exceeding 20% of the system then the certifier may request a replacement construction to current standard.
The above information does not relate to pool fencing requirements.
*Information taken from Queensland Building and Construction Commission