All renovation work must comply with the Building Code of Australia. A good rule of thumb is if you are intending to change the shape or structure of the house, then approval from your local council is needed. So if you are replacing your windows, you don't need approval, but if you are making the windows bigger, then you will need approval because you are changing the structure. Also if you are changing the intended use of a part of your house, then approval is generally required - for example, replacing the roller door on an integral garage with patio doors, to create a rumpus room. If the renovation work is to be completed by a builder, then he or she can submit the plans for approval. It gets a bit trickier, if you are planning DIY renovations, but most councils have a lot of information online. After the work is approved, council inspections will be take place during construction, to ensure building, electrical and plumbing work is compliant.