Blog Post #1 – Graffiti on Weathering Steel?

By: Héctor J. Berdecía-Hernández, Assoc. AIA

Materials Conservation Assistant, National Center for Preservation Technology and Training (NCPTT)

What is weathering steel? What is a coating? How does this relate to historic preservation? What are the differences between historic preservation and architectural conservation? These were some of the questions people asked when I told them about my current research. My name is Héctor Berdecía Hernández, and I am currently serving as a Materials Conservation Assistant at the National Center for Preservation Technology and Training (NCPTT). I received an M.Sc. Historic Preservation with a concentration on Architectural Conservation at the University of Pennsylvania. As part of my internship, I will try to answer those questions while sharing periodical updates on my research at the NCPTT.

I’m currently developing a self-directed investigation on conservation treatments, cleaning methods, and commercially available anti-graffiti coatings that may be suitable for use on Corten-weathering Steel. Removing painted graffiti from weathering steel substrates requires a thoroughly considered approach since the material is more porous than other metals commonly used in outdoor art and architecture such as stainless Steel, copper alloys, or aluminum. Graffiti materials such as aerosol spray paint and Sharpie marker can easily penetrate the distinctive patina of weathering Steel, and graffiti removal treatments inevitably involve interference with the material continuity of the surface. Because the corrosion patina of Corten-weathering steel is extremely vulnerable to abrasion, the cleaning process itself can disturb surface appearance greatly.

Corten-Weathering Steel – Source:

The proposed investigation aims to identify resources for recommendable coating choices to prevent undesirable alteration or even destruction of compromised weathering steel pieces. This research will explore the current state of the literature on recommended anti-graffiti coatings choices and cleaning treatments (which may not cause any visual impact and possible interference with patina development) of Corten-weathering steel. An ideal conservation coating provides sufficient protection to treated substrates, preserves the natural color, gloss, texture, and integrity of weathering steel substrates and adequately aids in the complete and safe removal of graffiti, without altering the appearance of the patina layer.

Graffiti on Corten-Weathering Steel – Source:








As part of the ongoing research, I will develop a comprehensive literature review and design a research study to evaluate and compare these selected coatings and treatments, which will be implemented by a conservation scientist at a later date. The study intends to assist preservationists and conservators both inside the National Park Service (NPS) and the cultural heritage community world-wide. This research fills a current gap in caring for weathering steel outdoor heritage in graffiti-prone locations by informing those selecting the most appropriate coating for their needs.

As an emerging architectural conservator, this internship has been an opportunity of being part of a pioneering research that contributes to my professional and research interests in architectural materials conservation.

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