During the construction of the Singer Tower, the original Singer Building was shored up and additional foundations were built. The top three stories of the old Singer Building, including the mansard roof, were temporarily taken apart in June 1907, so that four additional stories could be inserted above the existing seventh story. As such, the old eighth story of the old Singer Building became the new 12th story. This added of usable space without disturbing tenants on the lower floors. Several columns were erected at the old building's front and rear elevations, extending from the basement to the 11th floor to support the raised roof. Holes were created in the existing floors of the Singer Building so that they could be supported by steel columns instead of by the bearing walls. The old Singer Building was extended north by , with the three additional bays on Broadway designed in the same style as the original two.