An Affordable Housing Agency Retrofits a Historic Building and Builds a New Addition to LEED Platinum and Passive House Standards

The Pennsylvania Housing Finance Agency’s (PHFA’s) growth created disconnected departments, and additional space was needed for new employees to continue their affordable housing mission. The agency’s urban headquarters in Harrisburg was landlocked by deteriorating historic buildings and a small parking lot. Meeting the agency’s expansion needs on the small urban site, preserving historic building elements and integrating PHFA’s extreme energy-conservation practices were the biggest challenges of this project.

The historic Hickok Mansion and the newly constructed tower have their own separate Passive House systems.

To prepare for its expansion, PHFA purchased the adjacent deteriorating historic building, circa 1904. Known as Hickok Mansion, the dilapidated Georgian-Revival landmark is located within the capitol’s National Register of Historic Places district and, in 2011, the Historic Harrisburg Association placed Hickok Mansion on its list of endangered properties. PHFA spared the residence from the wrecking ball in favor of a more creative plan to integrate the historic structure with a new high-rise tower. PHFA worked diligently with neighbors, city officials and the Historical Architectural Review Board (HARB) for years to develop a design amenable to all parties.

A Complementary Tower

To begin, a non-historic 1970s Hickok Mansion addition was razed. The site for the new tower would be directly flanked by the oldest clapboard homes in Harrisburg. Extreme care was taken not to damage them during construction. A primary goal of the addition was to insert a new 8-story office tower within a 3-story neighborhood to complement the existing architecture while introducing a new aesthetic above that 3-story elevation.

Community collaboration was welcomed in the development of the design, and the addition went through multiple designs prior to the final contextual solution. Harrisburg has a very rich history of using brick on prominent buildings in the capitol city. Because this project is in a historical district, it was important to use brick as the exclusive material at the base of the new tower. High- performance glass predominates the upper floors of the building with a small section of precast panels uniting the existing and new structures visually. HARB approved the unique addition and appreciated the clean lines of the façade, which reinforces the modern aesthetic of this building in contrast to the surrounding buildings dating back to the 1800s.

Retrofit Challenges

The historic Hickok Mansion and the newly constructed tower have their own separate Passive House systems. The tower addition presented unique opportunities in the design, but the mansion was complicated and had numerous issues that had to be addressed. The historic façade was extremely porous and did not adhere to Passive House standards. A thermal air-barrier was constructed inside the historic exterior that was thermally insulated, airtight, adequately ventilated and mitigates thermal bridging. PHIUS-certified replica windows were also installed throughout the residence.

The exterior brick was cleaned and restored. However, the base of the residence had severe efflorescence, or crystalline salt deposits, caused by decades of the city salting the street and sidewalks. The façade brick and mortar had salt present two courses deep and the mortar was flaking and crumbling. Because of the severe salt damage, replacing the mortar was not an option. The design solution, approved by HARB, was to install a water-table treatment on top of the damaged brick base of the building to prevent any further damage.

The mansion’s front door was not ADA accessible, so its interior entryway was removed, and the exterior doorway was closed and preserved with a historic marker. A new entryway was constructed between PHFA’s original building and the residence. This new entrance is adorned with a canopy of fritted laminated glass and exposed galvanized steel, which juxtaposes the heaviness of the cast stone.

The residence interiors were retrofitted into a training center, community room and multiple conference rooms.

Roofing systems also were somewhat complicated. The western and southern portions of Hickok Mansion’s roof that are visible to the public had to maintain their historic vernacular. A new simulated slate roof was installed only on these areas to meet the historical requirements. A white TPO roof system was utilized on the remainder of the roof, which was installed lower than the slate roof. Not only does this roof reflect UV rays and heat from the building, which saves energy (and money) to cool the building’s interior during the summer months, but it also allowed VRF units to be installed on the roof, hidden from the public’s view.

“This project is one of the most innovative and creative building projects to be carried out in downtown Harrisburg in many years, as it combines two very important attributes,” says David Morrison, executive director of the Historic Harrisburg Association. “A sensitivity to historic preservation by virtue of its restoration and preservation of the landmark Hickok Mansion at Front and Locust Streets. Also, the design of the historical retrofit and the new adjacent tower to LEED Platinum and Passive House standards is an achievement that places this project in a class by itself in the country.”

A Healthy Work Environment

A staff-centric work environment is the result of careful space planning, as well as the application of 21st century interior design principles. The residence interiors were retrofitted into a training center, community room and multiple conference rooms. Technology, ergonomics, color, texture, pattern, and lighting combine to create a lively, comfortable and high-functioning workplace. Raised flooring systems are the source for heating, cooling and fresh air. Return-air ceiling plenums promote a healthy interior environment by removing all particulates from the staff areas.

PHOTOS: DON PEARSE PHOTOGRAPHERS INC. unless otherwise noted

About the Author

Benedict Dubbs, AIA, LEED AP
Benedict Dubbs, AIA, LEED AP, president of Murray Associates Architects P.C., is passionate about new sustainable spaces, adaptive reuse and diminishing urban sprawl.

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