670 Union Street
TYLin provided structural engineering design services for 670 Union Street in Brooklyn, New York.
Located between the Park Slope and Gowanus neighborhoods, 670 Union Street is billed as New York City’s first modern mass timber condominium. The six-story structure consists of a one-story steel and concrete-on-metal-deck podium topped by five stories of glue-laminated timber (GLT) planks on glulam beams and columns.
TYLin designed large-section glulam beams for column transfers. Steel straps and plywood splines connect the GLT planks into a single floor diaphragm. The floor structure was originally designed as cross-laminated timber (CLT) panels but based on the existing building code GLT was used. Glulam beams and floors are architecturally exposed in the building’s 14 units.
The development meets Passive House energy efficiency standards, the strictest criteria for energy efficiency. The structure includes solar panels, EV charging stations, and all-electric heating and cooling.
Project Highlights:
- The building’s lateral system is CMU (concrete masonry unit) shear walls at the core and on two sides.
- Shallow foundations support a one-story cellar.
- The main roof includes a recreation space.
- A rear extension over the parking area serves as a private roof deck.
- Units on the top three levels have cantilevered balconies supported on perpendicular GLT planks that extend past the facade.
Image Credit: Matthew Williams