The bank may not sign them because they have no knowledge of the property.
Keep in mind that when you purchase a property, you need to know if any additions were done with or without permits. The new owner becomes responsible for obtaining any permits on the property and/or returning it to it's approved legal use.
Do you due diligence and get copies of any permits related to the property so you know what your getting in to.
Allt he best,
Kat Becker, Realtor
Prudential California Realty
Don't be thrown off by the legalese
Have a realtor work on your behalf in this transaction. The Seller pays the commission but you need full representation.