100 Vandam Street

Blending History and Modernity in a Soaring Residential Tower

A portion of the existing wood-framed warehouse on the corner of Vandam and Greenwich Streets was retained and the six-story brick facade preserved to form the base of this 25-story apartment tower. Severud Associates designed new concrete slabs, shear walls, and columns supported by a concrete mat and drilled caisson foundation that integrate the historic charm of 1800s New York City with modern practices in design and construction.

Below-Grade Challenges

Originally, piles were recommended for the foundation. However, installing piles around the existing foundations that could not be removed beforehand proved prohibitively challenging. Instead, a concrete mat, augmented by drilled caissons and soil improvement, was chosen for flexibility in configuration and placement. The mat and walls were waterproofed and anchored to resist hydrostatic pressures resulting from the high water table.

Above-Grade Challenges

Designing a new structure to be constructed within an existing shell presented challenges beyond those typical of a mid-rise building. The relatively small site—about 60 ft. by 100 ft.—precluded any significant bracing inboard of the existing walls. Vertical support frames were cantilevered from the sidewalk and horizontal spreader beams installed on the exterior to temporarily brace the existing brick façade and cellar walls during demolition.

Modern Analysis and Design Processes

Engineers employed parametric and algorithmic analysis, which uses detailed three-dimensional models and advanced computational software, to optimize the design of the concrete elements. Despite the variation in framing needed to accommodate the unique location of planted terraces on each floor, significant reductions in column reinforcement and shear wall thickness and reinforcement resulted, which might not have been captured by traditional analysis methods.

Sustainable Design Features

In addition to preserving the historical appearance of its Hudson Square neighborhood, 100 Vandam Street contributes to a sustainable future by reducing waste and minimizing the need for new material, compared to a complete teardown. A landscaped loggia at the roof of the existing warehouse—accessible to all residents—and individual planted terraces on every floor enhance wellness. Slab edges extend beyond the exterior to provide shade and reduce heat gain.

Conclusion

100 Vandam Street is a testament to Severud’s ability to deliver innovative and sustainable structural solutions that respect the past while embracing the future.