"If prices fall even more, the banks will call for topping-up (not unlike a margin call).
Will never happen especially in the scenario you describe"
a home loan can last 30 years, but you sign up to a 2 or 3 year contract, where you then renegoitate your next rate.
when you take out a mortgage a bank will want somthing it can take off you should you fail to pay.
hyperthetically, lets say you bought a $700K home, price fell to $350K, in 3 years you paid off about $30K and need another loan for $670K but your assett your borrinwg against is only $350K
would a bank do it? specially if lots of loans are going belly up
