Practically 2nd mortgages are not preferred by banks.....since the firt mortgager has first charge(Security) and the second bank has second Charge...which increases the risk of the second bank.
If there is a significant difference between the market value of the security and the first loan, second mortgage is posssible..
For example if the first mortgage loan is Rs. 10 lakhs and security value is Rs. 11 lakhs.....the second mortgage wont be possible....
if the value of the security is Rs. 1 crore....second mortgage is possible...since the risk is low..