Thanks to good quality of both materials are today composite timber-concrete constructions suitable solution for new buildings and reconstructions of ceiling constructions of residential or civil buildings. In praxis can be found many ways how to create connection (joint) of timber beam and concrete slab. The methods of coupling are more and more sophisticated which carries bigger demands on control of implementation and technological practice. This paper describes laboratory tests and numerical and analytical modelling of timber-concrete composite beams with semi-rigid joints made of steel plates and convex nails.