The paper discusses the possibilities of hydrophobization of cement screeds intended primarily for external thermal insulation composite systems. The hydrophobic character of the mixtures both with and without the addition of hydrophobic agents was investigated. The following hydrophobic agents were used: zinc and magnesium stearate, sodium oleate, two types of mixed product of stearates and oleates, micronized wax and a silane hydrophobic agent. The mixture containing 0.6% zinc stearate and 0.6% silane showed the lowest water absorption and high flexural and compressive strength. The microstructure of the selected mixtures was also monitored using a scanning electron microscope, where the pores covered with the layer of polymer admixture were observed.