Balconies are elements of some multi-storey buildings. Thermo-insulated fasteners are components that connect balcony slabs with the building structure. Their main task is the transfer of loads in connections of balcony slabs with the building while also minimizing thermal bridges. The article presents analytical calculations performed to develop the new type of thermal insulated fasteners and to determine their load-bearing capacity. The aim of this article is to demonstrate that analytical calculations based on commonly utilized principles of reinforced concrete and steel structure operation along enable the development of the effective design algorithm of insulated fasteners and allow for a quick analysis of various geometric variants of these fasteners. The article presents the adaptation of typical algorithms for calculation of steel and reinforced concrete structures for the analysis of non-typical load-bearing capacity states that occur during the calculation of insulated fasteners. The load-bearing capacities of individual fasteners are shown in M-V interaction diagrams (bending moment – shearing force).