2023 AIA Housing Awards: The Block by ISA

The Block

Architect: ISA – Interface Studio Architects

Owner: Alliance HP 

Location: Philadelphia

Category:  Mixed Use Community Connection

Project site: Previously developed 

Building program type:  Mixed Use

Along one of Philadelphia’s major north-south connectors, The Block adds 49 apartment units through a building that successfully navigates the rift between the pedestrian-focused and car-centric realms. At a moment when many cities are struggling with soaring land and construction costs, The Block demonstrates an innovative low-rise and high-density approach to urban housing with potential applications for communities, both urban and suburban, across the country. 

Though Philadelphia is known for its walkability and dense urban fabric, there still exist car-centric commercial developments where big-box buildings on former industrial lots deliver retail amenities to historically underserved neighborhoods. This project bridges the gap between both conditions by supporting walkability and capitalizing on existing car-centric development. In place of high-rise luxury towers and their steep costs, the project probes the upper limits of lower-cost wood-frame construction types.

The Block was developed by the owners of a single-story warehouse that’s been transformed into a local brewery and retail space and sits immediately to the new building’s north. The owners approached the design team in 2017 seeking a concept that would add value and activity to the southeast edge of the parcel. To address the challenge of shaping a compelling living experience for city residents within a sea of surface parking, the team envisioned a broad mix of programming, including 11,000 square feet of ground-floor commercial space sized to welcome smaller, local tenants. 

The new building, set along the site’s southern edge, occupies the majority of the existing parking lot and lines 5thStreet with live-work units. Taking cues from Philadelphia’s low-rise rowhouse typology, the team employed an unusual approach to circulation throughout the building. The Block’s interior corridors are minimized, relying instead on an elevated terrace as the primary access point for the walk-up apartments. The terrace buffers the apartment entries from the surface parking lot and retail operations below and includes outdoor amenities off the central lobby and the building’s club room. From its decked seating areas, gravel lounge pits, and a turfed dog park, residents can enjoy views of the city’s skyline. 

“The use of conventional construction with tweaks on geometry and color has enlivened both its context and the life of tenants.” – Jury comment

Since its completion last year, all of The Block’s apartment units have been occupied, and numerous commercial leases have been signed. The owners remain committed to Philadelphia’s entrepreneurs and offer retail spaces for weekend pop-ups that attract nearly 100 vendors and makers. The apartments add much-needed pedestrian-friendly housing adjacent to transit and the city’s vibrant Old City and Chinatown neighborhoods. 

Project attributes

Year of substantial project completion: 2022

Gross conditioned floor area: 58200 sq. ft.

Project team

Architect: ISA 

Owner/Developer: Alliance HP 

Engineer – Structural: Cooke Brown Structural Engineers  

Engineer – Electrical: Holstein White Inc 

Engineer – Mechanical: Holstein White Inc 

Engineer – Civil: Bohler Engineering 

Landscape Architect: Jonathan Alderson Landscape Architects, Inc

General Contractor: Callahan Ward

Lighting: Lam Partners 

Photographer: Sam Oberter 

Drone Photographer: Plural VR


Catherine Baker, FAIA, Chair, Nowhere Collaborative, Chicago

John DeForest, AIA, DeForest Architects, Seattle

Brian Lane, FAIA, Koning Eizenberg, Santa Monica, Calif.

Amit Price Patel, AIA, DIALOG, Vancouver, British Columbia

Michael D. Robinson, AIA, Robi4 Architecture & Planning, San Diego

AIA Framework for Design Excellence

The AIA Framework for Design Excellence represents the defining principles of good design in the 21st century. Comprised of 10 principles and accompanied by searching questions, the Framework seeks to inform progress toward a zero-carbon, equitable, resilient, and healthy built environment.

Framework for Design Excellence / The Block

Design for Integration

Was there a design charrette?  Yes

Design for Ecosystems

Site area that supported vegetation (landscape or green roof) pre-development:  1%

Site area that supports vegetation post-development:  5%

Site area covered by native plants supporting native or migratory species and pollinators: 5%

Strategies used to promote Design for Ecosystems: Habitat conservation, flora/fauna

Design for Water

Is potable water used for irrigation?  No

Is potable water used for cooling? No

Is grey/blackwater reused on-site? No

Is rainwater collected on-site? No

Stormwater managed on-site:  100%

Design for Energy

2030 Commitment baseline EUI:  58 kBtu/sf/yr

Predicted net EUI including on-site renewables:  33 kBtu/sf/yr

Reduction from the benchmark: 43%

Is the project all-electric? Yes

Design for Well-being

Level of air filters installed:  MERV 9-11

Was a “chemicals of concern” list used to inform material selection? No

Do greater than 90% of occupied spaces have a direct view to the outdoors? Yes

Design for Resources

Were embodied carbon emissions estimated for this project? No

Design for Change

Estimated service life: 50 Years

Floor area, if any, representing adapting existing buildings:  0%

Ability to survive without utility power: Passive survivability

Which of the following risk assessment and resilience services were provided? None of the above

Design for Discovery

Has a post-occupancy evaluation been conducted? No, and a POE will not be conducted

Building performance transparency steps taken: Present the design, outcomes, and/or lessons learned to the office


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