enclosed patio without permit: a red flag for rental?

[Yiming Li]

Dear friends, 

I am first time investor and look for a good rental property in the San Fernando Valley area. Here a lot of house are built in the late 50's or early 60's and with a lot of modification. Specifically I see many houses have an enclosed patio room(not bedroom), which was built without permit. 

I am wondering for rental property shall I avoid this type of properties? what could be the risks of having tenants living in a house with unpermitted additions? 

Thanks a lot,

Yiming