The Block bridges the gap between the urban and suburban worlds, supporting pedestrian walkability while taking advantage of existing car-centric development in a novel mixed-use housing typology. Situated in Philadelphia’s Callowhill zone, The Block is located on 5th Street, a north-south connector linking multiple Philadelphia neighborhoods. The area is characterized by large-footprint 20th century warehouses and surface parking lots, many of which have been re-programmed with office, institutional or storage uses. The Block was developed by the owners of the warehouse immediately to the north, which was previously converted to house a local brewery and big box retail. Adding 49 apartment units within the existing surface parking lot on the southern portion of the site, the building lines 5th Street with live/work units and anchors the parking side with ground-floor retail. A pedestrian passageway cuts through the building at grade, and a social terrace above doubles as the main entry point for walk-up apartments.

The Block incorporates an unusual approach to circulation, taking cues from Philadelphia’s rowhouse fabric. Minimizing interior corridors, the building relies instead on an elevated, landscaped deck as primary access for upper level walk-up units. Conventional double-loaded layouts for typical multifamily buildings require substantial energy in conditioning of interior common space, and as a result, are typically designed with a minimum of shared social spaces. An unusually high level of spatial efficiency is achieved at The Block by eliminating the shared central corridor with walk-up typologies, allowing the project developers to instead focus investment on exterior social spaces connecting unit entries and acting more like urban streets. Reducing interior shared circulation space in turn reduced internal unoccupied conditioned areas, both saving money and reducing energy waste in common corridors. The project also encourages walkable lifestyles and energy independence, replacing a car-centric surface parking infrastructure with low-rise, high density housing.

Buffering apartment entries from surface parking and retail below, the deck features multiple outdoor amenity zones spilling out from the central lobby and clubroom. Decked seating areas, gravel lounge pits and a turfed dog park showcase views of the city skyline. Corner units are accessed through intimate interior stairs serving smaller groupings of four to six units. Live‐work lofts have street-level entrances and bi‐level units have entrances from the elevated deck, increasing the movement of people around the entire building, instead of privatizing this activity within a single entrance and concealed corridors. The elevated deck at The Block is treated as an essential part of the project, serving as access, egress, front porch and front yard. Its native plantings also slow rainfall from entering the building’s below-grade stormwater detention basin and ultimately the city sewers. Playful angular geometry and colorful walls enliven the building’s common spaces throughout.

Project Partners:

• Owner/ Developer – Alliance HP, Philadelphia
• Architect/ Designer – ISA
• Landscape Architect – Jonathan Alderson Landscape Architects, Inc.
• Structural Engineer – Cooke Brown Structural Engineers
• MEP Engineer – Holstein White, Inc.
• Contractor – Callahan Ward
• Civil Engineer – Bohler Engineering
• Lighting Design – Lam Partners