The next time you walk into a space exuding a sense of history and grandeur, look up. If the ceiling overhead comprises masonry tiles arranged in a herringbone pattern and raised mortar joints, you may be due a free lunch with MIT architecture professor and 2008 MacArthur fellow John Ochsendorf, the organizer behind Palaces for the People: Guastavino and America’s Great Public Spaces. Now on view at the National Building Museum (NBM) in Washington, D.C., the exhibition is the first major show about Guastavino’s legacy in American architecture. More than 600 buildings in 36 states—including such iconic structures as Grand Central Terminal and the Washington National Cathedral—are known to contain the soaring arches, vaults, and staircases built with the distinctive lightweight, self-supporting, and virtually indestructible clay masonry tiles.

Rafael Guastavino emigrated to the New York with his son, Rafael Jr., in 1881. Unable to find work as an architect, Guastavino leveraged his experience as an established master builder in Barcelona, says architectural historian and NBM curator Chrysanthe Broikos. Embracing the American enterprising spirit, Guastavino patented a tiling system based on the traditional building methods behind Catalan vaulting. From 1881 to 1962, Guastavino Co. worked on projects across the country with architects who were drawn to the system’s structural and fireproof properties, as well as the tiles’ aesthetic. Through Guastavino’s construction methods, “the grand visions of architects were able to be built for much cheaper,” Broikos says. “Guastavino was integral to informing what great buildings could be.”

With 25 patents ultimately to their name, the father and son raced to keep up with the changing times in architectural design and construction. Examples of their innovations, in everything from acoustical and decorative products to material handling, are on display along with historical drawings, records, tile samples, and project photographs. Don’t miss the built-on-site masonry vault, a half-scale replica of a ceiling vault at the Boston Public Library, Guastavino’s first American commission and where this exhibition debuted last year.

Before scheduling your lunch with Ochsendorf, check to see whether someone else has already documented the potential Guastavino vault. If so, the free lunch is off the table. (Disclosure: My nearly decade-long quest to discover a vault began when I was one of Ochsendorf’s graduate students. It has been in vain.) Through Jan. 20, 2014.

Editor's note: This article was updated since first publication to clarify the terms behind the free lunch.