I visited a client last weekend in Rosanna and they had an interesting situation. The home they owned in Rosanna was very old and in need of a total renovation. The clients sort quotations from builders for the renovations and were given quotes around $400k. Their request of me was to provide a cost for a knock down rebuild solution in lieu of the renovation. 

The site had a lot of slope around 6 meter from back to front meaning significant earthworks would be required. The knock down of their old home would cost $14k and sit costs came in at around $55k leaving $331k for the rebuild of a new 32 square home. Total cost for the knock down rebuild came in at $400k and the best part is the home is brand new designed to suit my client's requirements. 

In comparison to the renovation the costs were the same but the rewards are much greater with the knock down rebuild. 

One major point of difference is that the rebuild is new and you are starting with a blank canvas once the knock down has occurred. Designs suitable to your family can be achieved and realised with a knock down rebuild which are very hard to incorporate in a renovation of old design.