The search for rational and effective design options is a very good motivation for research in the construction industry. In particular, the construction of inter-floor ceiling is one of the most important elements of any building or structure, and its cost is approximately 20-30% of the total volume of all construction and installation work. Therefore, one of the problems faced by the designer is the choice of the most efficient floor covering, including in terms of efficiency. The vast majority of loads are transmitted to the framework, walls and foundations through the overlap, the actual weight of which can reach up to 70% of the total vertical static load, therefore the search for new constructive solutions for the creation and study of lightweight types of overlays, which will reduce the constant component of the load, remains relevant. Given the constructive complexity of the facilitated effective forms of overlap, the question of adapting existing methods for assessing the bearing capacity for the engineering calculation of such structures is important. The article describes a brief overview of existing studies of multilayer structures and ceilings with void inserts. The engineering methodology for calculation of bearing capacity of multilayer and claydite monocoque (with void-forming inserts) of slabs of overlappings, with their bullying in four corners is given. The bearing capacity of multilayer boards was checked for strips 250 mm wide in the middle of the extreme contour, where the maximum moments are in operation. To determine the bearing capacity of monocoque floor slabs, their calculated section was reduced to a tread section. The calculation of the considered slabs is based on the deformation technique, taking into account the nonlinear diagram of "tension-deformation" for concrete and two-line for reinforcement based on the actual physical and mechanical characteristics of materials, in accordance with the current normative documents, in particular DSTU B V.2.6-156: 2010. The comparison of theoretical calculation results with the performed experimental researches of multilayer and monocoque floor slabs is given. Graphically depicted designs and design schemes for the obstruction of prototype samples. It is suggested to use a coefficient of efficiency Kef, which allows to evaluate the efficiency of such structures compared with the classical reinforced concrete and choose the most optimal variant, which is reflected on the example of the test plates.