This is going to be an even bigger issue in NSW with the new limit of two years for claiming against non-structural defects. Non-structural means that it's not involved in actually holding the building up – leaking balconies slip through the net. Some lawyers are advising new apartment owners to plug their balcony drains, flood them and see if they leak before it's too late to clam.
Re Home Insurance Warranty, in NSW it's not required by builders for structures over three storeys high.