Abstract: Pin point foundations are formed, the ground is flattened and levelled at the level of these foundations, peripheral recoverable shuttering is disposed on the ground and continuous rows of non recoverable shuttering defining the ribs are disposed at the center. The rows of shuttering are spaced apart by baryte cardboard elements providing sealing and insulation. On the upper face of the non recoverable shuttering are disposed means for spacing the trellis work reinforcing the floor. Then the concrete is poured by pumping and, after drying out the floor, only the peripheral shuttering is recovered.