Polyurea manufacturers and users emphasise many properties of this product, so it is necessary to take a closer look.

Indifference to humidity

It is true that polyurethane systems are sensitive to humidity and water. A polyurethane can also react with atmospheric humidity. The result is a carbon dioxide gas which causes foaming or bubbles and craters. The reaction between component “A” = ISO and component “B” = POLYOL (polyamine) of the Polyurea system is so fast that there is no time for the reaction with humidity to start. This is why the Polyurea system is insensitive to humidity and water, and does not usually produce carbon dioxide bubbles. This is an important advantage in areas with a humid climate. In addition, this system helps if the substratum is wet or if there is a concentration of humidity. However, it is not a good idea to apply Polyurea on a wet surface, especially when good adhesion is required. To be precise, a clear division between the systems cannot be established. Some polyurethanes can be formulated with excellent tolerance to humidity. Some manufacturers have recently developed a new generation of elastomer and structural polyurethanes which have excellent properties of insensitivity to humidity and water. Many, although not all, have therefore overcome this problem. Although insensitivity to humidity is therefore the only reason for the choice, it must be said that the polyurethane can also be applied equally effectively.


Another advantage claimed by the industry is that polyurea can be sprayed onto wet surfaces or even on ice, without reacting, expanding or deteriorating. In part this advantage really exists, but it is also necessary to consider the very bad adhesion in such cases. In the case of the presence of water or humidity, adhesion is completely compromised. There is a specific industrial standard (ISO -NACE -SSPC etc) according to which the surface must be carefully prepared by applying a primer. Therefore, the underlying humidity must perforce be eliminated in order to apply the primer. However, there are also some small applications for which the polyurea can be directly sprayed on cement, even damp cement, and in this case there can be advantages.

Contact FUTURA for specific guidance on your specific application.