Split Zoning Philadelphia

[Mayer M.]

Hey,

Would anyone know how split zoning works in Philly?

I have a 6650sf cmx 2.5 lot and and large RSA5 lot behind it. It’s my understanding you can add 20% to the CMX 2.5 lot by taking away from the RSA5 lot which is considered split zoning, but am I permitted to use that extra 20% of the RSA5 lot in my density calculations for CMX 2.5? If I can, can I build on it or does it have to remain open area?

Thanks!!!