The buildings’ walls are also heavily insulated. What had been exterior brick walls became interior walls. Wood I-joists were bolted onto the walls to form a 9 1/2-inch-thick insulation cavity filled with blown-in fiberglass insulation. Below grade, the retrofit incorporated mineral-wool board at 2 5/8-inch thick and another 2 inches inside the wall. “This level of insulation radically reduces heat loss and dramatically improves occupant comfort, resulting in heating and cooling energy demands approximately 90 percent lower than code construction,” Hindle explains.
The designers also paid careful attention to heat recovery, moisture-recovery ventilation and space conditioning. They used four enthalpy-wheel energy-recovery ventilators with a glycol-filled ground loop passive pre-heat/pre-cool coil, yielding energy recovery of approximately 82 percent. The ventilators delivered filtered fresh air and exhaust continuously, creating balanced ventilation, which protects building durability, interior air quality and comfort.
Financing and Attention
The owner of Weinberg Commons, Washington-based Transitional Housing Corp. (THC), a non-profit whose goal is to end family homelessness by 2020, recognized there would be upfront hard and soft costs. Hindle asserts Passive House buildings pay back a good ROI. However, THC’s primary motivation to undertake PH was not economic. It was to provide more stable, resilient, comfortable housing options for low-income families. The owner’s representatives believed retrofitting all three buildings rather than just one would allow them to help 36 families rather than just 12 for only a marginal upfront cost increase. In fact, traditionally, the cost increase for a Passive House retrofit is between 10 and 20 percent. For Weinberg Commons, it was 12 percent above typical gut-renovation construction.
Funding for the project was arranged under the auspices of THC. The corporation, which will hold the buildings long-term, received a $500,000 capital grant over two years from The Harry and Jeannette Weinberg Foundation, Owings Mills, Md., toward the total development cost of $10.5 million.
The Weinberg Commons approach to financing and design is already receiving attention from the housing community. In March 2015, The University of Maryland School of Architecture, Planning and Preservation, College Park, honored THC for its work at Weinberg Commons with The Maryland Innovation and Entrepreneurship Awards, which commemorate “the most imaginative successes of the year”.
In November 2015, Weinberg Commons was one of the stops on a tour of innovative housing, sponsored by Greenbuild International Conference and Expo, which is dedicated to green building. Fine addressed the group of 50 designers who were on the sold-out tour, and Thomas W. Hutchinson, AIA, FRCI, RRC, CSI, RRP, principal of the Hutchinson Design Group, Barrington,
Ill., gave the group an expanded view of the environmental benefits provided by the EPDM roofing membrane, including a 45-year track record of performance in the Washington area and in similar climates.
Hindle points out the greatest barriers to Passive House construction are restrictive policies that set caps on construction costs for affordable housing while not crediting the building for future energy savings. “If they were to take the whole number and figure out a formula that would allow them to spend more on the envelope so they could deliver future energy savings, this could happen every day,” he says. In addition, if businesses were to realize their future savings in energy costs, passive design would be a popular design approach for office buildings and other large structures.
Now that the construction phase is over, Weinberg Commons has achieved its most important goal: providing affordable housing for low-income and formerly homeless families. Washington, D.C., has a severe shortage of low-income housing. This project is a successful example of reusing building stock, maintaining current communities while raising the standard of what affordable housing can be. “I had countless passersby ask me when the condos would be finished,” Fine notes. “The public perception is that any radically new and different construction means ‘in with the haves and out with the have-nots’. This project breaks that pattern.”
There was an official ribbon cutting for Weinberg Commons on Nov. 6, 2015, attended by Washington Mayor Murial Bowser. The units were fully leased by the end of November. (The occupants, low-income or formerly homeless families, applied to the District of Columbia government for access to the housing.) Now, as the occupants stay comfortable during the cold Washington winter and hot summer to come, the passive housing approach is paying immediate dividends in personal comfort for the families who call Weinberg Commons home.
Photos: Zavos Architecture & Design