The main material of the manufacture of floor slabs is reinforced concrete, less often — concrete. Concrete is used either light or ordinary heavy brand at least 200. Often you can see plates in which a round section cavities are located along their entire length: this approach is used to maximally reduce its own weight of the plate without any significant loss of its strength-in hollow slabs a special knitting of the reinforcement is used. In ribbed reinforced concrete floor slabs, the additional strength of the structure is achieved due to 1.5 m of stiffness located at a distance of 1.5 m.
