This paper presents an experimental study on sand-lime bricks. The purpose of this research is to examine different materials as modifiers, in particular barium aggregate. Undoubtedly, the properties of the sand-lime products depend on many factors such as raw materials, preparation or autoclaving conditions, etc. The research was carried out and analyzed by scanning electron microscope (SEM) in order to improve acoustic isolation of calcium silicate bricks. As a result, it was possible to determine the phase composition in the structure of the calcium silicate products.