Can I build on a boundary line?
Generally speaking you can build your garage / carport 150mm from the fence line, providing the average height of the building (including gable peak) is no more than 3m high. Alternatively, the average height can be up to 3.6m if you build 1000mm (1m) from the fence. Unfortunately there is no in between, it is either 150mm or 1000mm. Some other restrictions may apply depending on your property and local council requirements.
For Rural properties the council may have specific requirements in terms of shed siting. A quick call to the council will determine this requirement (height restrictions still apply).
Commercial and Industrial buildings on boundaries are required to conform to fire regulations and must have a "fire rated wall" (such as Hebel or Concrete Panels). Some other restrictions may apply depending on your property and local council requirements (such as space for fire vehicle access).