According to EU Directives, it is necessary to improve the energy consumption of buildings. Therefore, the aim of this article is to improve the physical properties of foamed concrete produced on the basis of light plaster mortar. For this purpose, polystyrene granulate with a bulk density of 13 kg/m3 in the amount of 4, 7 and 10 g of 1 kg of light plaster mortar and a foaming agent in the amount of 2, 4 and 6% of the cement mass were used. Density, thermal conductivity coefficient and mechanical properties (compressive strength and tensile strength in bending) were determined. It can be observed that with the increase in the content of addition of polystyrene granulate, density, thermal conductivity coefficient and sorptivity were decreased, what is a positive phenomenon. However, at the same time, a reduction in mechanical properties was demonstrated. With the increase in the content of addition of foaming agent, density, thermal (except 2% of the foaming agent content) and mechanical properties were decreased. While sorptivity of all samples is lower than the basic sample, but sorptivity increases with the addition of a foaming agent for samples of samples with the addition of polystyrene granulate.