Main image: Bob Polett Photography
When the Pennsylvania Housing Finance Authority (PHFA) was ready to expand its 2004 LEED gold-certified headquarters in Harrisburg, they re-enlisted the same architect to surmount the challenges posed both by the landlocked urban site, a historic building component and its energy conservation goals.
The 3 800m² expansion includes the construction of a new eight-storey tower and the retrofitted renovation of the adjacent historic Hickok Mansion, both designed to the latest Passive House and LEED platinum sustainability standards.
The agency’s urban headquarters was landlocked by deteriorating historic buildings and a small parking lot. Its exponential growth meant that additional employee space was required for the company to continue its affordable housing mission.
The latest sustainability features by Murray Associates Architects entail an electrochromic curtain wall system, VRF mechanical systems, 77 solar panels and a living roof that was integrated to align with the state’s energy-efficiency criteria.
Noteworthy is that since its completion in January 2020, the building has used 50% less energy than similar structures built to standard codes. PHFA also delivers 20% of its solar panel electricity production back to the city grid.
PHFA purchased the adjacent deteriorating historic house (c. 1904) on Locust Street, which is within a National Register Historic District. In 2011 it was listed as an endangered property by the Historic Harrisburg Association. Through numerous public workshops with Locust Street residents, the Historical Architectural Review Board and city officials, the design scheme proposing glass on the upper floors of the tower facade received overwhelming support.
The interior was retrofitted for a training centre and conference rooms. The new glass, precast concrete and brick tower blend old and new within the neighbourhood context. Its internal wall assemblies have insulated metal panels for controllable airtightness, minimising thermal bridging.
The tower footprint was an impervious parking lot and the former non-historic Hickok House addition. The top four floors cantilever over the historic building and are crowned with a living roof and other natural materials. A new entrance for Hickok House was constructed in the Front Street areaway and the original entrance was preserved. A translucent canopy of fritted laminated glass and exposed galvanised steel juxtaposes the new entrance’s cast stone.
Meeting the sustainability standards
The new office addition utilises high amounts of energy with its elevator, equipment, appliances, computers and monitors.
To meet LEED platinum and Passive House criteria, multiple systems were integrated to offset energy consumption. These include:
• An electrochromic curtain wall system of 129 panels to reduce energy consumption through programmable tinting managing solar gain and light harvesting.
• VRF mechanical systems to provide comfortable and efficient heating and cooling zones while providing comfortable conditioned airflow.
• A photovoltaic system of 77 solar panels to return 20% of its generated energy to the utility grid.
• A living roof to manage stormwater runoff, extend the roof life and reduce carbon-dioxide emissions offsetting global warming.
PHFA’s addition reduces operational energy consumption and improves performances in energy savings, water efficiency, carbon-dioxide emissions reduction, improved indoor environmental quality, and stewardship of resources. Through self-monitoring, PHFA has documented 50% less energy usage than a similar structure built to standard codes.
Historic building, modern compliance
The Historic Harrisburg Association, Capitol Area Neighbours, the City of Harrisburg and PHFA worked together to find a way in which the agency could expand, without demolishing both Hickok House and 110 and 122 Locust Street Clapboard homes around the corner. In doing so, the exterior of Hickok House has now been restored with new multi-paned PHIUS certified windows and a water table treatment replaces the bricks that had deteriorated.
A thermal barrier wall system was constructed inside the original facade, addressing the inefficiency of the 1904 building’s exterior envelope, preserving its historic authenticity and mitigating thermal bridging. The original entrance didn’t meet ADA compliance, so a new entrance now exists between the two PHFA buildings. The first-floor multipurpose meeting room is freely available to the community.
The 129 panels of electrochromic curtain wall system reduce energy consumption through programmable tinting and managing solar loss and gain. Every five feet by ten feet panel is segmented into three controllable zones. The 20cm thick insulated precast concrete wall and the curtain wall components were modelled for shading reduction factors.
An elegant stairway is located adjacent to the original headquarters, with a suspended monumental glass staircase that encourages staff wellness as they circulate through the upper four floors of the tower. The base of the stairs doubles as an impromptu collaboration space, with its marble flooring and iconic seating.
PHFA’s expansion by Murray Associates Architects sets a new benchmark of how to use the latest principles and methods to bring a historic building component and its energy conservation goals into the 21st century, creating a new lease on life and meeting the highest sustainability standards.
For more information on this project, visit https://www.worldarchitecturenews.com.
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