The composite slabs are made of bubbledeck type slab elements with spherical gaps, poured in place on transversal and longitudinal directions.the minimum distance between gaps is 1/9 of the gaps diameter. the total height of the bubbledeck slab elements is constant. function of the diameter of the bubbles that are used, the total height may be: 230, 280, 340.the elements are delivered as manufacturing made elements, consisting of a precast concrete layer with 60 mm thickness in which is embedded the bottom part of the reinforcement shell of the entire slab element, the bottom part of the spheres that make the gaps and, function of situation the hvac tubes.