Always Check Your Builder's
10 tips to win your building dispute
for Australian home building & renovations
GET INDEPENDENT ADVICE EARLY
Speak to your local building or consumer office.
They've also got building inspectors who can help provide you with some independent expert opinion.
If it's a big problem, then perhaps you might like to speak to and shortlist a few lawyers with suitable expertise.
You will learn a fair bit by this exercise, and you might well need one of them.