How Can I Remove Graffiti From My Historic Masonry Building and Prevent It From Reoccurring?
Graffiti is not only an irritating eyesore and source of visual blight in our community, but it can be destructive for historic masonry buildings. The key to eliminating graffiti—and preventing it from reoccurring—is to remove graffiti as soon as it appears. Spray paints are the most common type of graffiti, but solvents and paint strippers capable of removing spray paints are harsh and abrasive, may discolor or stain masonry surfaces, make it more difficult to remove paint, and potentially damage the masonry. There are ways to remove graffiti, however, from all types of historic masonry without damaging the historic surface or substrate by breaking the bond between the paint and the masonry surface. This requires knowledge of 1) the materials used to make graffiti, 2) the masonry, and 3) cleaning methods and materials. The first step is to identify the type of paint. The most common graffiti materials are spray paints (Polyurethanes, lacquers, and enamels); brush-applied paints (oils and synthetic resins such as vinyls, acrylics, acetates, methacrylates, or alkyds), and permanent felt markers. But other materials can also be used, such as water-soluble felt markers, ballpoint pens, chalk, graphite and colored pencils, pastels, wax and oil crayons, liquid shoe polish, and lipstick. Paints are composed of 1) pigments, 2)binder that holds the pigment together, and 3)a solvent that allows the pigment/binder to flow. They are applied wet and harden as they dry. Therefore, the longer they are allowed to remain on the surface, the harder they are to remove. The second step to assess the condition of the historic masonry prior to beginning graffiti removal. Masonry encompasses all types of natural stones; manufactured clay materials such as brick; and cementitious materials such as cast stone, [...]