Selected Answers

From Zenith Czora of Durotech Industries, Inc. on January 2, 2017:
I wish I could a attach a photo here to justify m ...read more I wish I could a attach a photo here to justify my comments. Based on my research and lab work on evaluation of different types of so called anti-graffiti coatings, it is dependent on what the customers specify and how long the efficacy would last. Temporary anti-graffiti coatings  based on waxes won't be beneficial to a porous sealer, due to residues being left on the pores and crevices after graffiti removal, which eventually results in poor recoatability unless recoating with the same type of anti-graffiti coating. With a semi-permanent anti-graffiti coating, mostly water-based materials, the film is also being removed when using a solvent-based graffiti remover. There are some penetrating anti-graffiti sealers, but they do not really protect the substrate from graffiti. So far, the best anti-graffiti coating is a moisture-curing material based on organosiloxane. The cured coating provides excellent release and ease of removal of graffiti and aerosol paint by water and without using a solvent-based graffiti remover. The only drawback on this coating: it changed the appearance of the substrates due to to its glossy finish, which enhances the structure and profile of the surfaces. Also,  the coating remaining in the container needs to be used up due to its sensitivity to moisture, which leads to surface skinning and increased viscosity.

From Tom Schwerdt of Active Transportation Advocates on February 22, 2016:
Jaime, I am not aware of any manufacturer marketin ...read more Jaime, I am not aware of any manufacturer marketing polyureas for anti-graffiti. What advantage does it have over the standard polyurethane and silicone chemistries?

From Jaime Molina of Primary Materials Inc. on February 18, 2016:
An expensive alternative for new concrete would be ...read more An expensive alternative for new concrete would be a 2-coat system as follows. First, coat with a non-film-forming sealer. This puts a nanoparticle in every pore and will prevent any graffiti from penetrating deep into the concrete. Then topcoat with an industrial flooring polyurea, such as those used in garages. These present a non-porous, glass-like surface, and should be impervious to most solvent-based graffiti as they are formulated to withstand gasoline, motor oil, and other strong chemicals. Actually, you might skip the first coat. It should last at least a decade .

From Tom Schwerdt of Active Transportation Advocates on February 17, 2016:
"Best" is such a loaded term, and there are inadeq ...read more "Best" is such a loaded term, and there are inadequate surrounding details. The "Best" approach is to make the porous masonry inaccessible in your structure design so that it cannot be graffitied. Any type of anti-graffiti coating will require maintenance, and picking one (or none) requires that you determine the maintenance preferences of whomever is going to be doing the maintenance. It is a common designer hubris (or laziness) to pick the "best" anti-graffiti coating without first trying to mitigate the need for the coating through limiting access with design, and second getting the input from the people who will do the maintenance. Do they prefer solvent cleaning? The use a polyurethane  anti-graffiti. Pressure washing? Then use a silicone  anti-graffiti. Patch painting? No anti-graffiti, just supply them with a matching paint. High- pressure, grit-injected pressure washing? Just stand back.

From travis gold of Mid Atlantic Coatings on February 17, 2016:
Put it behind a tall fence with barbed wire. Just ...read more Put it behind a tall fence with barbed wire. Just kidding... Your best bet is to apply a glossy, abrasion-resistant coating like a fluoropolymer. The budget method would be to apply an acrylic  masonry coating and budget for touch-ups.

From Douglas Pearce of Eagle Specialized Coatings And Protected Environments a div of DW Pearce Enterprises Ltd on February 16, 2016:
Seal it with an aliphatic polyurethane so that it ...read more Seal it with an aliphatic polyurethane so that it is no longer porous.