You have 2 issues here. One is finance (which I will leave to the mortgage brokers) and the other is whether or not your block will suit a granny flat build and if it does - whether you will go down the Private Certifier route with a 10 day approval or whether you have to go down the DA route which is a 6 week minimum process with Council.
A guy like brazen from the forum here, who is Serge at
http://www.grannyflatapprovals.com.au/ will be able to assist.
If your block is suitable, then go down the Private Certifier route and stay the hell away from Council...QUOTE]
Thanks for the kind plug Propertunity.
To the OP: I can let you know 100% whether the granny flat can be approved or not and under which legislatiuon (Private certifier vs Council). This will cost you zero. just a phone call, so you wont be taking a gamble before you go for goal.
What you
will need to pay for initially is for a Site Survey, property searches and some profesional reconnaisance to see what other factors might affect your build cost:
1. Sewer mitigation
2. Tree removal/avoidance
3. Slope of land (Excavation)
4. Building Site access
5. Drainage mitigation
6. Demolition costs...
These things can add a lot to a build so it's well worth a small initial investment to have these assets surveyed and reported on, no?