Frequently Asked Questions
Cement & Concrete
Technology Home > FAQs > Graffiti
Q:  How
can I remove graffiti from concrete?
A: Many products are
suitable for removing spray-paint and felt-tip markings from concrete
surfaces. These products are generally effective also for removing
crayon, chalk, and lipstick. The manufacturer’s directions should
always be followed. If satisfactory results are not obtained with
the first remover tested, a second or third attempt with other products
should be made.A single product may not remove multiple types of
stains.
Several proprietary chemical strippers are available,
many of which contain a citrus-based solvent, methylene
chloride, or potassium hydroxide. Citrus-based solvents are the
least aggressive and may not work on certain paints, but they are
the safest to use and often have less stringent disposal requirements.
For best results, allow products based on potassium hydroxide to
soak into the concrete surface for several hours before rinsing.
These products also require a subsequent application of an acid
neutralizer.
Abrasive cleaning can remove graffiti, but it will
also remove the outer layer of concrete, making it more vulnerable
to weathering. The cleaned area may also look different from the
rest of the surface. After the graffiti is removed, or preferably
before a structure is placed in service, a graffiti barrier coating
or sealer should be applied. The surface treatment should keep graffiti
out of the concrete pores and on the surface for easy removal.
For more information see Removing
Stains and Cleaning Concrete Surfaces
(IS214)
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