Can I make my own repairs on a flip?

[Matt Hummer]

In North Carolina where I flipped my last house, I was required to use the property I was flipping as my primary residence in order to legally make repairs to it and I had to live in it for one year prior to selling it.  There were two ways around these rules: Hire contractors who would pull required permits, or be a licensed general contractor myself.  I have several questions for the group regarding making repairs to a flip in Philadelphia:

-Can I buy an investment property and make all repairs myself if I'm not a general contractor?

-Are there holding requirements in the event that I make repairs myself?

-Am I required to use the property as my primary residence?

-Am I required to pull permits for cosmetic, non-structural work that I do myself?

-Are there any major "gotchas" that I might not have addressed related to rehabbing a property in Philadelphia on my own?

Thanks,

Matt