Hydrophobic impregnation serves to reduce capillary water transport in mineral building materials such as natural stone, bricks, renders and concrete. The tendency of such surfaces to absorb water leads to a range of problems. Pores in the materials become susceptible to freezing and frost when filled with water. Salts and corrosive gases may also penetrate. And the presence of water in the pores also gives rise to biological growth in the form of algae, lichens and fungi. With our Nisiwa and Emcephob hydrophobic agents, pores near to the surface and susceptible to capillary absorption are temporarily impregnated to prevent the penetration of moisture. At the same time, the surface remains open to water vapour diffusion. Water and contaminants are repelled by the concrete as long as the hydrophobic treatment remains active.