The architectural committee of the Philadelphia Historical Commission on Tuesday refused to allow the owner of one of Philadelphia’s best examples of Art Deco buildings to change the structure’s distinctive blue color to gray-white.

Justin Detwiler, an architect and member of the architectural committee, said there are few buildings in the city for which color is “as integral to the design and the significance of the building” as the WCAU building at 1618 Chestnut St. The committee asked for a paint analysis and review of historical documents to determine what the accent colors were on the decorative elements to more closely match the blue color of the original textured facade finish.

“It seems like such a small thing, but on this building more than almost any other, it’s so crucial to its design,” he said.

The architectural committee approved other renovations, including new windows and a one-story rooftop structure and pergola, to the former home of the CBS radio affiliate WCAU. Any doors that are replaced must match any historical documentation of the old doors that can be found, the committee said. And the only signage allowed is at street level, not on the tower or side of the building as proposed.

The architecture firm leading renovations of the building wanted to create a neutral canvas to highlight the ornamental features of the building, said Luca Segato, project manager at Eimer Design. But the firm is open to adjusting the color. Historically, small blue glass chips dotted the gray stucco of the building, according to the application to the architectural committee. Sometime before the building’s historic designation in 1981, the facade was covered in stucco, which was then painted blue.

Detwiler said that he understood the owner’s point about wanting to make some design elements pop more but that the owner could alter the facade to more closely match its historical color "without going as far as making it an off-white, rather blank facade.”

“The wayfinding nature of the color of the building is kind of iconic," he said. "And I think if you can embrace that, I think it’s really important here to honor that.”

The 10-story building with office space on the upper floors was formerly occupied by the Art Institute of Philadelphia, which closed in 2018. Old Navy occupies the retail space on the ground floor.

The full historical commission must give final approval for renovations to the building.