Pedestrian Tunnel Helps Mixed-Use Project Flow Between Urban Street and Parking Lot

Just North of Center City Philadelphia — in a rapidly transitioning light-industrial and warehouse district — architecture firm ISA designed an award-winning, small-scale, mixed-use project nestled between an active urban street and the edge of a surface parking lot.

ISA founder Brian Phillips, who also served as the principal in charge of the project, told LoopNet that when his firm was “introduced to the site, it was … unclear in which direction the area would go.” It might have remained industrial or begun to evolve toward a mix of uses.

That unsettled state necessitated a flexible design that would incorporate industrial, commercial and residential elements, as well as bridge an urban street and a surface parking lot that could someday be redeveloped.

The building sits on about 1.5 acres of a roughly 7-acre parcel owned by developer Alliance HP. Other uses on the site include a brewery and a shopping center anchored by Target. Phillips said the vision for the lot was to add housing to the site without disrupting parking, while also favorably impacting the parcel’s other uses.

Those marching orders led ISA to create an innovative four-story structure with residential and commercial uses; a unique carve-out at ground level connecting the street to the parking lot; an elevated terrace that functions as both a lobby and a greenspace; and several work/live lofts.

In the process, ISA also successfully blended residential, commercial and industrial aesthetics in the same structure.

“What's interesting about Alliance partners is that they're not [traditionally] a housing developer,” Phillips said. He added that they generally focus on repositioning commercial and industrial buildings. “I think part of what they thought with this building was ‘if this is going be our first residential building, we want it to say something, we don't want it to be just a product.’ And I think that was really bold.”

The resulting four-story, 58,200-square-foot, mixed-use building comprises 80% residential and 20% commercial uses. The Block features 49 market-rate apartment units: 28 are one-bedroom, 20 are two-bedroom and one is a studio. Along the front of the building on 5th Street, nine units are two-level lofts that can function as residential, commercial or live/work structures.

A bustling component of the project is the elevated outdoor terrace that sits atop the building’s commercial space facing the parking lot. The colorful and warm space serves as the project’s outdoor gathering place and hangout, but it also functions as its front yard.

One of the unique design elements of the project is that most of the residential units open directly to the elevated terrace. Phillips noted that this design approach, while seemingly unconventional, is one that is familiar in Philadelphia. “They're almost like a series of row houses that sit on top of the patio,” Phillips said.

Row houses above the street along a park “is a little bit of a Philadelphia model,” Phillips said. He added that “when people come home up these stairs and go in a door and up more stairs, that's not an unfamiliar experience in Philadelphia.”

With residents coming and going to and from their units from the terrace, the space serves as a primary circulation artery for residents. This flow makes the terrace function as a lobby as well as a rooftop.

Some might wonder who wants to sit on a terrace that overlooks a parking lot. But Phillips noted that “if you sit on the terrace, a parapet wall almost edits out the parking lot and you just see the view of the city skyline.”

A generous ground-level tunnel in the center of the building serves as a welcoming alcove that connects the urban street to the back of the building. The east side of the alcove provides access to the residences and the west side features commercial storefronts that continue along the back of the building at ground level.

“We wanted to acknowledge the importance of the parking and the circulation of the bigger site while still maintaining the 5th Street urban edge,” Phillips said of the tunnel.

A big opening in the ceiling toward the back of the tunnel “was also a fun way to get communication between the ground plane and the upper terrace,” Phillips added, making it “a place where people on the ground can understand how the building works.” It also serves as a covered outdoor space where activities like pop-up flea markets have taken place.

Philips noted that sometimes commercial space in Philadelphia is hard to lease, while apartments lease up more quickly. “So, we wanted to come up with a type … that’s a kind of rogue entrepreneur space.” For example, he said one of the loft units is a yoga studio; the proprietor lives there and also conducts yoga classes in the unit.

He added that in a city where live/work is not formally acknowledged by the zoning code, one question was “how can we make an apartment that flexes, that a therapist or a graphic designer can use?” Phillips noted that the loft façades are reminiscent of storefront windows, making them ideal for residents working from home.

A concrete deck supports the landscaped terrace and provides separation between the residential and commercial areas of this all-new structure. Below that is a steel super structure with stick-frame infill. The residential units above are framed with wood.

Exterior materials include standing seam metal, brick and Hardie panels that Phillips said gave them latitude to paint in fun colors. There's wood cladding on the inside of the planters, a wood pedestal paving system to warm up the terrace and various gravel zones.

“Playfully contemporary” is how Phillips described the design aesthetic, preferring to stay away from the term “industrial” because he said that is hard to define. “There is metal cladding as part of the domestic vernacular … but contemporary is my best way of describing it; it's of our time.”

Speaking to the project’s hybrid nature, Phillips said “it does have a little bit of a positively commercial vibe because it's in and around a lot of commercial buildings. But I think one of the things that was really fun was that the ‘people layer’ on the back terrace, using wood and color, acknowledges the interaction of people in that area of the building.”

And the façade, he added “does feel a little bit like it could be housing or a small office building. But then on the back you have all the color and the character.”

This unusual site does call for a unique building, Phillips said, noting that “if it were just a double loaded corridor apartment building, it would feel out of place on the parking side; and if it was a strip mall on 5th Street, it would feel out of place on that side.”

ISA received an American Institute of Architects (AIA) 2023 Housing Award for its “exceptional residential design” of The Block.