Last year, the 50-year-old buildings that now make up Weinberg Commons were neglected, run-down, and empty. The three-story, brick-and-block buildings date from an era when single-pane, aluminum frame windows were considered enough to protect the inhabitants from a cold winter. Today, the three buildings are award-winning examples of energy efficient design, and provide affordable, efficient housing for low-income families in Washington, D.C.
The buildings underwent intense retrofitting, designed to lower energy costs throughout the project, and ensure that one of the buildings meets the rigorous energy standard of Passive House (PHIUS+). The retrofit used energy efficient materials and extensive insulation under the roof and in the walls, designed to lower energy use for heating and cooling in the buildings by as much as 90 percent, and reduce its carbon footprint through its lifetime. Weinberg Commons is Washington, D.C.’s first multifamily Passive House and designed to approach net-zero energy consumption.
A black EPDM roofing membrane was chosen for its proven track record of long term performance, sustainability and energy-saving potential that the dark surface provides in colder, northern climates. The membrane helps meet the requirement to limit the amount of energy used to heat a square foot of living space on the coldest day of the year to 68 degrees Fahrenheit.
Polyiso, rigid foam insulation that offers the highest R-value in the industry, was installed below the membrane. Four base layers of insulation boards were staggered and installed along with tapered insulation to promote positive roof drainage. The resultant R-value far exceeded code requirements providing an average of over R-55. The project also incorporates other energy-saving features, such as triple-paned windows with redundant compression seals to minimize air infiltration.
“The Passive House design principles at Weinberg Commons minimize energy consumption by its occupants and normal building operation through robust envelope design and integrated systems. Only after that, did the development consider utilizing renewable energy sources,” said Matt Fine, CPHC, LEED AP, project manager and director at the Frederick, Maryland-based Zavos Architecture+Design, the firm responsible for the retrofit design. “The combination of appropriate insulation, disciplined air sealing, tuned solar shading and high-performance windows, balanced ventilation with heat recovery, and minimized thermal bridge construction all contribute to minimize the risks of moisture. At the same time, the buildings are designed to consume very little energy.”
The apartments provide 36 affordable apartment units for low-income families including 12 homeless or formerly homeless families with below-market rents, employment services and other support for youth and families. One-third of the units are reserved for families with more intensive needs.
The project was developed by the Transitional Housing Corporation (THC), a nonprofit that provides housing and comprehensive support services to over 500 homeless and at-risk families in Washington, D.C.