Wind Driven Rain Resistance of Silicate Mineral Paints

Mineral paints differ in their properties compared to acrylic paints. Acrylic paints form a tight film on the surface which is completely impermeable to water going in and moisture in the structure escaping out. Mineral paints on the other hand form a microporous matrix which is completely fused with the surface. The pores of silicate mineral paints are small enough that liquid water is not able to enter but moisture trapped in the structure can escape in the form of vapor.

One of the common methods for checking for resistance to wind driven rain water is the RILEM tube test. The RILEM tube resembles a test tube with an open flange bottom that can be stuck to the surface with the flange either in a vertical or horizontal orientation based on the orientation of the surface.

Fig 1. Example of a RILEM tube test on a vertical brick wall

The tube is then filled with water and a hydrostatic pressure builds up on the surface that pushes the water into the surface. A drop in level of less than 0.2 mm in 20 minutes indicates a surface that can withstand wind driven rain from a class 1 hurricane.

Another method to test against wind driven rain is ASTM E514.

Thus, Zydex Silicate Mineral Paints are highly water resistant while simultaneously being breathable. A unique combination that keeps your structures dry and free from damage (See our article on “What is Paint Breathability and Why is it Important?”).