Is it legal to have a personal loan on top of a bank loan?

[Dirk Heite]

I offered an off market SFH in Oregon $510k, bank financed and a side $30k loan at $1500/mo. This was my creative way to meet her $540k asking price and my need to keep the loan below $484k so I can get a conventional loan. I plan on house hacking. Her initial reply was positive then she came back and said "I'm told that doing a contract outside of the sale contract isn't an option cause it actually would invalidate the sale contract. So many rules....🤦🏻‍♀️".

I do not know the laws, but I'm thinking the second $30k loan is just between her and I and should have nothing to do with the $484k loan with the bank. Am I wrong? If so, how can we do this legally?