The article deals with the design of appropriate properties for a brick raw material in the production of frost resistant product. Additives based on bentonite and zeolite were added to the brick clay at doses ranging from 1 to 10%. The test samples were fired at 1055 C. The achieved results indicate that the initial material should not contain a high proportion of substances that increase the pore volume. Increased pore volume can cause not only the presence of organic matter and carbonates, but also an inappropriate particle size distribution of this initial material. When assessing the frost resistance a well known empirical relationship by Maage has been used. Authors conclude that this empirical relationship is only suitable for a limited number of brick products. In this case plays an important role the particle size distribution of the input raw materials material and the firing temperature. At the same time these products would need to be exposed to freeze-thaw cycles for long time periods before determining of the pore structure.