We have developed a calculation procedure for wood-concrete mixed structures with deformable connection, subjected to bending, which takes into account the cracking of concrete under tensile stress, reducing the impact resistant section. The study was aimed at the rehabilitation of old wooden floors, so that enhanced the original structure to be able to respond with full guarantees to current safety requirements, while maintaining its original appearance, which in many cases the architect is often a target to perform. Given the complexity of the practical application of this procedure, has also developed a software that enables a simple, both input and output results, with its further development, has lead to the achievement of graphs, as well as make a valuable aid to the calculation, we provide an overview of the behavior of the system, linking the many variables involved