Author

NOVESKY, M.; GERNS, E.
Wiss, Janney, Elstner Associates, Inc.

Abstract

In the United States, the most dramatic change in building construction was triggered by the industrial revolution of the late 19th century. The ability to economically manufacture steel shapes lead to the development of the skeleton frame building system. As a result, the structural function of the exterior facade was no longer necessary. Masonry facades could be treated as a skin that wrapped the skeletal frame.
Early skeletal frame skyscrapers frequently incorporated projecting masonry cornices and water tables as both decorative and functional features of the buildings. Support of these elements varied greatly, but generally consisted of embedded steel assemblies. As these buildings aged, the distress resulting from the corrosion of the embedded steel led to the deterioration (cracking and spalling) and ultimately the demise of many of the early skyscrapers’ exterior decorative masonry elements (terra cotta, brick or limestone/sandstone). On some buildings, the projecting elements were removed to reduce the potential of falling masonry from building facades.
This paper will review corrosion related distress in masonry facade materials and methods ofremediation, prevention and repair. Case studies of the original detailing and support systems as wellas the subsequent distress and restoration options for masonry materials on historic skyscrapers inthe United States will also be discussed and compared.

Key words
Masonry Restoration, Repair, Historic Skyscrapers, Cornices, Water Table, Corrosion