Philadelphia permits for rehabs

[Marshall Secord]

Hi BP, I'm trying to do some research for Philadelphia building permits needed for single family home rehabs and it all seems so convoluted. I just sold a property that I completely rehabbed myself without a problem. I may have gotten lucky because it sold for cash, so a bank never got a chance to snoop around and check on permits. For that project, the biggest alterations I made were a new kitchen, new light fixtures, floors, an outdoor privacy screen and I converted a half bath into a full bath. Could I have gotten in trouble with any of this if my buyer got a mortgage rather than bought it cash? 

I'm currently in the process of buying another house that has a huge, deep basement that I want to totally finish and I also want to add a bathroom. Are these things that I need permits for in order to not get myself in trouble when I sell the place? I'm planning on using contractors on this one, but not sure what can be done with no permits vs EZ permits vs some other building permits and where and when I might need engineers and inspectors to review plans and ensure that work is being done to the permit standards. Any clarification would be greatly appreciated. Thanks!