10-18 47th Avenue cold formed steel detailing
Long Island City, NY
This conversion transformed a three-story 1900s home into a modern luxury two-family dwelling with a backyard and roof deck, while doubling the existing square-footage. A full height addition was built onto the back of the existing structure. A glass atrium atop the central stair in the upper unit and the rear glass façade floods natural light throughout the space.
In order to achieve this transformation and extension without undermining the existing wood building supported by wood party walls shared with the neighboring properties, a new structure was designed inside the existing building and extending out in the rear.
The structural system is cold-formed steel floor joists supported by cold-formed bearing/shear walls build inside of the existing wood bearing party walls. The building was retrofitted with a new wind/seismic lateral system consisting of cold formed steel shear walls and steel moment frames in the front and rear of the building.
Madsen was the Engineer of Record for the building but also provided cold-formed steel shop drawings for this project. The complete set of shop drawings contained plans, sections, profiles and product component locations, including anchorage, bracing, fasteners, accessories and finishes. Connection details with screw types and locations, weld lengths and locations, and other fastener requirements were designed and provided.