The random character of mechanical properties of building materials reveals itself when construction structures are tested even though all prescribed technological standards and requirements are met. The paper presents software implementation of the algorithm the statistical straggling of the mechanical properties of materials in the design of structures. This algorithm is built into the software AnSysBuildingBlock (ASBB), developed by us, whose interface is presented here, and which can automatically generate the code for the settlement complex ANSYS. Consider an example in which the impact of scattering mortar mechanical properties on the stress-strained state of brick masonry and its structural destruction was investigated.