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Citylight Exterior Rendering


Religious Assembly, Early Childhood Education
Adaptive Reuse, Deep Energy Retrofit
30,000 SF
Philadelphia: Manayunk

Built circa 1850 on the banks of the Schuylkill River, the Roxborough Mills building is being transformed into a long-term home for Citylight Church. This project examines the challenges of designing in a rising flood zone, renovating a 175-year-old building, navigating Federal and Local Historical registers, and marrying these complexities with aggressive carbon goals. The building program leaves the ground level unoccupied as a sacrificial flood zone, while the second floor will include a 500-seat assembly worship space, prefunction areas, office space and both adult and early childhood education facilities. The project is an exemplary model of adaptive reuse architecture in the face of a rapidly changing climate, by incorporating building science, life cycle carbon and operational costs into a holistic conversation about long-term preservation. Once constructed, it is modeled to use one half the embodied carbon of comparable new construction. After the rooftop photovoltaic system is installed, it is projected to use one fifth the operational carbon compared with the regional average for this typology.

Citylight Axon


Passive House Principles: PHI EnerPhit program framework

Philadelphia and Federal Register of Historic Places

Special Flood Hazard Zone

Environmental site remediation

Native landscape restoration

Building Geometry:

Heat Loss Form Factor: 2.4

Window to Wall Ratio: 17.4


Building Metrics:

Predicted Energy Use Intensity (pEUI): 35 kBtu/sf/yr, 15 kBtu/sf/yr with future Solar PV

Embodied Carbon: 393 CO2e (A1-A3 Cradle to Gate)

Building Envelope:

Slab on Grade: Existing to Remain

Floor/Ceiling: R-43
Above Grade Walls: Average R-22
Roof: R-30

Windows: U-Value 0.20, SHGC 0.32

Skylights: U-Value 0.17, SHGC 0.26


Building Systems:

Power / Fuel Source(s): All electric
Renewable Energy: Solar ready for future 66 kW rooftop PV system
Heating & Cooling: Air-cooled, heat recovery, variable refrigerant flow (VRF) heat pump
Ventilation: High efficiency energy recovery ventilator

Domestic Hot Water: Heat pump water heater

Low-embodied carbon building envelope
Appliances: Energy-Star
LED lighting


Project Team:

Owner: Citylight Church

Builder: The Norwood Company

Owner’s Rep: Watchdog
Structural Engineer: Larsen & Landis
MEP Engineer: J+M Engineering 
Civil Engineer: Ruggiero Plante Land Design 

Acoustics/AV: Threshold Acoustics

Landscape Architect: Apiary Studio

Passive Building Feasibility: bldgtyp

Historic Preservation: Heritage Consulting

GeoTechnical: GeoStructures

Solar Feasibility: Solar States

Lighting Agency: Diversified-Group

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