Converting 3 family to 4 family home Philadelphia

[Alyse Oz]

I have a 3 family home in West Philadelphia (it is current vacant and needs to be rehabbed).  While trying to get estimates from contractors, I had one contractor tell me that I should split the first floor apartment into 2 separate apartments and have 4 units in the building instead of 3.  It does have 2 separate entrances from the outside.

It is currently like this:

1st floor - 3 bedroom apt (but very strange layout)

2nd floor - 2 bedroom apt

3rd floor - 1 bedroom apt.

He says I should change the 1st floor so that it has two 1 bedroom apartments.  It would mean adding an additional bathroom and kitchen, but getting a lot more rent.

I'm worried about the additional city requirements though. It is zoned RM1, the contractor says i can easily change from 3 unit to 4 unit multifamily without a lot of headaches (sprinkler etc).  Is this true?  The property currently has fire-escapes, does anyone know if i have to pay an outside company to certify it, etc. for 3 unit properties vs 4.