In an attempt to appreciate the Guastavinos’ contribution to public spaces at a period when the image of this American city was being consolidated, this article provides an overview of the preliminary studies, projects and major restoration works performed on their works in New York City. The text not only gives the names of the principal researchers, professionals and case studies, but evaluates the different interventions carried out to date on their most emblematic buildings, paying special attention to the matter of acoustics in their interiors.