New York’s Crotona Park’s Historic Clock Tower Lanterns Revitalized with EXTECH’s Custom Glass Block Assembly

September 01, 2021 - by commARCH
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New York’s Crotona Park’s Historic Clock Tower Lanterns Revitalized with EXTECH’s Custom Glass Block Assembly

Image Credits: Oleg March, courtesy of EXTECH

Project Background:
For more than 80 years, the iconic towers have served as a landmark and destination during the day. At night, the glass lanterns are illuminated from within the building, beckoning neighborhood residents and park guests. After more than 80 years of use, EXTECH helped renew this Landmark Site’s architectural heritage with modern performance.

1700 Fulton Ave., Bronx, New York.

Image Credits: Oleg March, courtesy of EXTECH


Owner/architect: City of New York Parks and Recreation
Glass block lantern – contractor: Sandhu Contracting, Inc
Glass block lantern – designer, engineer and fabricator: EXTECH/Exterior Technologies

The project was completed on March 2021.

What was the challenge?
Recognizing its “special character, special historical and aesthetic interest, and value as part of the development, heritage, and characteristics of New York City,” the Landmarks Preservation Commission considered it “one of the great WPA ‘Art Moderne’ structures of the Depression era in New York. The complex, along with the other WPA-era pools, was a major accomplishment of engineering and architecture, and is recognized as being among the most remarkable public recreational facilities ever constructed in the United States.”

Crotona Park’s pool building has remained in use almost every summer for 85 years, but was primarily designated for seasonal programming. While repairs had been made through the decades, its conditions had deteriorated.

What was the goal?
In 2015, NYC Parks announced a new vision: “Crotona Park will be the most beautiful park in the Bronx and a haven for the community with recreational opportunities for every age.” Fulfilling this vision, the “Crotona & Tremont Park Master Plan 2034” outlined a long-term effort that included restoring and converting the existing pool building into a year-round recreation center. Calling urgency to this major project, the plan noted, “It is a very significant structure that needs immediate attention.”

Image Credits: Oleg March, Courtesy of EXTECH


What was done?
Part of this larger reconstruction project, renovation of the clock towers’ lanterns began in 2018. “The goal was to replicate the historic look of the original glass blocks, adding modern performance to the structural assembly,” explained Ron Clelland, EXTECH’s Architectural Representative in New York. “Clear blocks were selected for their transparency, contributing to the lantern towers’ warm, welcoming glow at night, which can be seen from a distance.”

Both of the clock towers’ lanterns are similar on all four sides. Each side of the four-sided glass block structures are approximately 10 feet long. The vertical sides are composed of dozens of hollow 5-3/4- by 5-3/4- by 3-7/8-inch blocks. These walls are joined together by custom, 90-degree, hollow glass blocks at the corners. Totaling 3 tons in weight, more than 1,100 blocks are positioned within stainless steel framing, which is concealed by a white mortar. The mortar’s color was selected for historical accuracy by the Landmarks Preservation Commission.

Along with the correct glass block sizing and mortar formulation, EXTECH verified the project’s precise design requirements with shop drawings and a submittal mock-up. To ensure both the aesthetic and performance requirements were met, EXTECH prefabricated the entire system under factory-controlled conditions.

EXTECH manufactured the glass block assembly with special removable hoisting rings so Sandhu Contracting’s on-site team could more easily lift the large, prefabricated units by crane and accurately set them in place. Drawings illustrating the step-by-step installation process also supported Sandhu Contracting’s efforts in the field.

What was the result?
The clock towers’ lanterns reconstruction was completed on schedule late in 2020. Clelland concluded, “Achieving all of the goals for these lanterns took lots of collaboration between the NYC Parks’ architects, Sandhu Contracting and EXTECH. It’s rewarding to see the results of our work will continue to attract people to Crotona Park’s revitalized pool building and play center for many years to come.”

What product was used?
EXTECH’s Custom Clear Glass Block Assembly.

EXTECH/Exterior Technologies, Inc.’s mission is to improve lives through innovation in daylighting systems, natural ventilation and other unique building envelope systems. Redefining the intersection between the natural and built environments, EXTECH manufactures and designs wall, window, skylight, canopy and custom façade systems.

Learn more by calling 800-500-8083, emailing or visiting