[JoelyE95 (Joel)]

Chris,

Under the 2014 Town Plan, it would likely come under "Domestic Outbuilding".

Domestic Outbuilding - "A Class 10a building, as defined in the Building Code of Australia, that is ancillary to a residential use on the same premises and is limited to non-habitable buildings for the purpose of a shed, garage and carport."

Furthermore, the max height is 2.4m with an average height of 2.1m. Obviously this dome exceeds this, so you would need to consult with a Private Building Certifier for any structure assessable against the Building Act 1975. This would require at a minimum a good, clear sketch of your proposal and intent to be able to get assessed. Upon completion, you will then be issued with a new Certificate of Classification for the premises. Without this, Council can issue you with a "Show Cause Notice". If you can not show cause and gain approval, they can then make you pull the structure down.

Joel

Caveat - I am in the developing, building and construction industry and know what is required, however you should conduct your own searches with Council and the Certifier to get an approval. I know of one nearby that should be able to help you out.