Oh - one more thing. MONEY. Not trying to put you off the idea, but ...

Say you buy an old house on a big block that suits your requirements for $400k (pulling numbers out of thin air here). You demolish it straight away costing $20k, then subdivide for $40k, then you start to build. While you are waiting for all this to be approved, *someone* has to pay interest on $460k (less deposits) and that is a lot of money and depending on the council you could be waiting up to three years from buying your house to moving into your new house.

Can you really afford that? What legal protection are you going to have if there are multiple people involved in purchasing the land? You might have a falling out during that time or one couple finds their dream house elsewhere and wants out, leaving the other couple with the full debt.

Also you may have huge difficulties getting a loan to build the house, if you have say 2 couples involved in the initial purchase and all 4 people are on the loan, while they won't tell you this upfront, when it comes to assessing serviceability (how much you can repay) the banks will decide that each person is responsible for the whole $400k not $100k each, and when it comes time to get the loan to build the house you find you are all in too much debt to get extra money for the house because of the way the bank deems responsibility for the debt.

Just things to watch out for.