Welcome to Permit Philly's Philadelphia Multifamily Zoning Guide!

If you'd like to meet the other parts of this series, click hither .

Oh my god we're back again.  We've covered Commercial MiXed-employ (CMX) and Residential Unmarried-family unit Fastened (RSA) zoning in our Philadelphia zoning guide.  Now it'south time to tackle Philadelphia multifamily zoning.

In Philadelphia, multifamily zoning is for buildings that are allowed to hold – mind, yous may desire to sit down here – more than one family.  I know.  Information technology's heavy knowledge.

Just that'due south not quite every bit uncomplicated as information technology sounds: multi-family might non have anything to exercise at all with families in the auto, two kids, and a dog sense.  "Family" here just ways a living space in a edifice.  Multifamily buildings tin have multiple units in a place.  So sometimes, multifamily buildings look about the aforementioned as RSA-5 buildings; but they've got a unit or two in there.  Other times, they're more manifestly just larger apartment buildings.

But y'all want to know more about this mysterious classification, considering you are reading a zoning blog!  Let's dive in… later on one important question:

Can I plow my single-family building into a building zoned as multi-family unit?

It'southward like you didn't even read the last post in this weblog!  So hither it is over again:

Technically, no: no one beside City Council members tin can change zoning in our fair town.  Nevertheless, you tin use your unmarried-family building equally a multifamily building if yous get a apply variance from the City'south zoning board.

This is harder to practice than it used to exist, because while the zoning code is very restrictive and a lot of multifamily units have been re-zoned in recent years as unmarried-family units, the electric current zoning chair does not similar single- to multi-family conversions.  It'southward not impossible!  Only pick your spots and have a banging plan (with pictures!) to have care of trash and parking.

Moving on…

Philadelphia Multifamily Zoning: RM-1 through RM-4

Whatsoever building with an RM designation tin exist used as a residence: for one family or equally a multi-unit edifice.  However, at that place are limits to how small each unit can be.  In an RM-1 building, the minimum unit size varies: for the outset ane,440 feet of square footage, you have to use at least 360 sq. ft. of lot area for the units.  If your edifice is bigger, then awesome!  … But yous accept to use 480 sq. ft. of lot area per unit.  Them'due south the breaks.

You lot can as well use any of these buildings, as you can RSA buildings, as religious institutions – if they're not attached to anything else.  Information technology's a similar idea for schools, although you do have to get a special exception for that.

For business concern use, you will need a variance – the "Certain, why not?" permit – from the Zoning Lath of Aligning (for a tertiary time, that link is here).

Important observe: RM dimensional zoning rules are basics crazy insane

The basic rules most units and acceptable uses in RM buildings are easy to follow.  However, the other rules – like, answers to the question "how large can this edifice be?" – are what nosotros in the biz call "bonkers."

Commencement of all, unlike in other categories of the zoning code, there's no exact pattern to the numbering.  RM-ane is the smallest category… but RM-2 is the biggest.  RM-4 is also pretty pocket-size.  Go effigy.

RM-4 buildings are not required to accept any infinite betwixt them and the sidewalk: there'due south no minimum setback.  But the larger RM-2 and RM-three buildings are required to have a setback; and the RM-ii setback is determined past calculating 75% of the buildings height and and so measuring back from the center of the street.  (If yous know why this is, I want to meet you and learn your wisdom.)  The RM-1 setback, meanwhile, must line upwards with the setback of the whole block; equally in RSA-five evolution… because remember how RSA-v is the smallest RSA category but RM-one is the smallest RM category?  No?  You didn't think that?  Weird.

Anyway, this stuff is pretty wild and doesn't fit an like shooting fish in a barrel pattern; so if yous want to know what's up, go to the source: the dimensional tabular array itself.  At that place aren't a whole lot of rules of pollex to apply in this category.

Philadelphia Multifamily Zoning: RMX-1 and RMX-2

1 of the wild cards in the game of Philadelphia multifamily zoning is the RMX designation.  RMX buildings function a lot like regular RM buildings – yous can use them as houses; of grade, just likewise as schools or hospitals with special exceptions.

RMX buildings, still, can also exist used every bit businesses; so long as you follow strict rules (laid out here) governing how much of the concrete building is used as a home and how much is used equally a business.

Y'all are probably asking, "Why does this category exist?  What'due south actually the departure between this and the CMX category?"

Let me tell you:  I have no thought.  The Philadelphia Lawmaking says that it's trying to utilise RMX buildings to preserve historical features… simply really, that's the sort of thing you can exercise by slapping a historical designation on a building, or throwing information technology in an Overlay District (don't fifty-fifty ask).

RMX is a weird idea that basically exists just so that Philadelphia tin can have some extra rules; which is definitely what Philadelphia needs.  (And also *cough* is why sometimes yous demand a crack let consultant to guide you through Philadelphia multifamily zoning.)

Philadelphia Multifamily Zoning: RTA-i

But await!  What about the lowly duplex?

Philly has a zoning designation for duplexes, too: RTA-ane.  That'due south "Residential Two-family Fastened" to you.  In that location'due south simply one category; and information technology's not super frequent.

This designation is mainly for existing buildings that are essentially two houses attached in the middle; similar so:

Philadelphia Multifamily Zoning - RTA-1 Homes

These buildings are allowed to be used exactly like a small rowhome (RSA-5): no businesses; no multi-family living; but churches or hospitals are okay if the building isn't fastened to annihilation or (for hospitals) you ask the Zoning Board of Adjustment get-go.

The only real difference between this designation and RSA categories is that you can have 2 units in it.

So do we as Philadelphians really need this designation?  Hey, far exist it from me to say that the Philadelphia Code is comically specific to the indicate of occasional uselessness, but I did just type that sentence.   And you notwithstanding need permits; considering craziness and all, you yet dear Philly (and are keenly enlightened that multifamily properties are worth more).  So make it impact with Permit Philly, and we'll practice all the heavy reading for yous.