Legislation provides for a minimum 120 days defects liability so that your builder may complete the home building work. The 120 days begins on the same date as practical completion. (Practical Completion is the date which the building work is ready for use - ie with reference to homes this is the day that you can move in.) In short this means that although your house may not be finished the builder has 120 days to finish the work, so long as that work does not stop the building being lived in, or otherwise used for the intended purpose.