Timber-concrete composite panels cause certain interest now due to possibility to combine advantages of pure timber and pure concrete panels in one structural member. The structures have to be designed, considering behaviour of such composite panels in order to benefit from these advantages. In the analyse of load-carrying capacity for timber-concrete composite panels, subjected to flexure, the important component is connection system between concrete layer and timber, which affects the stress distribution and the deformations of the structure. Behaviour of timber-concrete composite panels, with the rigid timber to concrete joint, were evaluated in this research. The rigid timber to concrete joint was developed by the using of the crushed granite pieces as the keys in combination with the perforated steel and carbon fibre reinforced plastic composite tapes to increase effectiveness of the structural materials use. Behaviour of the timber-concrete composite panels were investigated by the transformed section method, finite element method and by experiment for the purpose of this study. Four timber-concrete composite panels with the span in 1.8 m were statically loaded till the failure by the scheme of three-point bending. Perforated tapes made of S355 steel grade with the dimensions 2000X45X3 mm and total area of perforation in 10% were used in timber to concrete joint. Possibility to increase by 19% load-carrying capacity of the timber-concrete composite panels by the adding of perforated steel tapes was stated. Maximum vertical displacements of the panels decrease by 25% at the same time.