What’s average rehab cost in the Philadelphia area

It ranges depending on size and finishes but I'd use at least $85/ft of occupied space for single family, but I personally budget $100/ft for rough numbers and the nicer projects I do. Multifamily is even higher due to fire ratings, fire alarms and sprinklers plus more kitchens and baths packed into a small box. There are investors that get it done for less but they're few and far between and usually have their own people on staff or have a long standing relationship with a GC and do dozens of projects per year, or are about to get ripped off and just don't know it yet.