You the recent purchaser of a house have legal rights to have issues repaired that are incorrectly built or fail during this 5 year warranty period under the Building Workers Contract Act.
Australian consumer law also states that goods must be of acceptable quality, fit for a purpose, acceptable in appearance, free from defects, safe and durable for a period of 6 years.
This means you can challenge your building issue in court for up to 6 years, however it is an expensive option, as court representation fees of around $50,000 would be expected.
After 10 years no claim claim be made against a builder or tradesman in either the magistrates court or the district court.
My point of view is that the easy option is to say that after looking at the building report, you do not want to buy this house and to use your cooling off period to walk away. This is why you have this option in the purchasing contract.
If you have knowledge of the issues and are happy to purchase still, that is fine too. But remember that to challenge anything in court will be expensive, slow and it is not easy process, as some court cases take years.