Nearly six years ago, when a sudden gas explosion in Manhattan’s East Harlem neighborhood leveled two five-story apartment buildings, one of the six Calvert Lancaster buildings—a residential building abutting those buildings—remained standing.
Curtis + Ginsberg Architects, based in New York City, were the architects behind Calvert Lancaster. The firm specializes in affordable and multifamily housing, hoping to bring benefits to users and the community with every project it completes. As a LEED Silver structure, Calvert Lancaster was originally built in 2012 to emphasize energy efficiency. Designed using insulated concrete form (ICF) construction, the exterior walls were formed by pouring concrete in a rigid foam form framed with steel rebar—which is what kept it standing after the explosion.
“Everyone in Calvert Lancaster building got out fine,” says Curtis + Ginsberg Architects partner Mark Ginsberg, FAIA. “There were only a few cracks in the concrete—remarkable, considering the impact of the explosion. The ICF facing those two buildings got a little charred, but didn’t burn. It’s a good fire break, with 6 or 8 inches of solid concrete.”
A few years later, when Curtis + Ginsberg Architects was selected to design Beach Green Dunes, a multifamily project located next to an elevated subway line in Far Rockaway, N.Y., they chose ICF construction for its ability to reduce noise transfer and keep the subway sounds where they belong: outdoors.
In addition to offering structural integrity and sound absorption/reflection, ICF construction also maintains interior comfort levels in climates like the Mid-Atlantic by reducing the impact of outdoor temperatures on the indoor environment. “With ICF you can be near a window or outer wall in the winter and not be cold,” Ginsberg says.
In fact, Ginsberg uses ICF construction in his New York City designs more than nearly any other architect—and he chooses this approach when possible for several reasons.
“ICF provides a simple way to build an energy-efficient, cost-effective envelope,” he explains, which has helped Curtis + Ginsberg Architects achieve LEED and Passive House certification for several building projects.
Because ICF blocks not only serve as the building’s structure but also as the insulation and air/vapor barrier, Ginsberg says they lessen the number of building materials needed to complete projects, which can decrease timelines and the number of trades and construction steps necessary as well. “Once ICF blocks are up, you’re much further along in the process than with wood or traditional concrete,” he says.
Contractors can find value in this as well, using ICF blocks because they’re light and fast to install. No heavy equipment is needed, and fewer laborers are required. As a result, contractors can maximize their resources and get more work done in a shorter amount of time.
Ginsberg also appreciates that it can be used to create nearly any design aesthetic: modern, traditional, Gothic, etc. “Any type of building typically done in a block bearing wall can be done in ICF. There’s nearly endless design flexibility.”
To learn more about designing with ICF, visit BuildWithStrength.
