Is it presently occupied or vacant? If it is occupied do you need the income to qualify for the purchase?
If you are buying it to convert, it is allowed, do you need additional money to do the construction?
If it is a construction loan, do you plan on living in it when it is complete? If so you may want to see if the bank will provide you the mortgage to buy it, the construction loan to renovate it and the end financing.
Depending on your relationship with the bank ie: have you done this type of development before? you will most likely need 20 - 30% down payment.
I would speak to a LOCAL bank (saving & loan) not a national lender, as they will be more likely to make the process go smoothly.