The biggest factor against doing this as a business is that in most states you need a builder's licence if you're going to manage it yourself. Fortunately for you, I believe WA has an exception for "non-structural works", but no such exception exists in QLD or most other states (even though many people think that it does ).
Even so, make sure you're familiar with the regulations applicable to you with regard to safety at the worksite, contractors having insurance, etc.
Even so, make sure you're familiar with the regulations applicable to you with regard to safety at the worksite, contractors having insurance, etc.