I just saw the news that "a record 229,438 new homes approved in the past year". Given the average household in Australia houses 2.5 person, and the population growth last year (to March 2015) is 316K, we only need 126,400 to sustain the housing. I understand that there are replacement needs for some properties, but that shouldn't be a huge number. So the question is: are we over-building? During the middle of last decade, the US housing boom (and the bust) was partially driven by the "spec developers" who speculated the house price growth, and overbuild beyond the long term average of new housing supply. Are we in the same situation?