Buying a property with a non-permitted addition

[Jacob Rincon]

Hello,

I'm in process of making an offer on an off market property that is 1210 sq feet, but there is an non-permitted addition that was made some years back. It is an add on patio room/sun room that is 220 square feet. Is there anything i need to do prior to rehab of the home? Do i need to get it permitted through the city and explain my situation? Any advice would help greatly, and as always thank you in advanced.