Suitable concrete cover to the reinforcement for durability must be provided for either solution. When using standard precast components which have been designed for normal internal use then the cover provision must be checked against the exposure condition. Such components often have secondary steel used in manufacture which is too close to the surface. In addition post-tensioned wires often extend to the ends of the unit. These details create few prob- lems when used on internal ﬂoors but in the environment of ground ﬂoor slabs could prove problematical.
Fig. 9.46 Suspended ground ﬂoor slabs.