The project to reinforce and repair the ceiling in the building at via SS Quatro 45 resulted from an order from the civil court in Rome caused by the excessive weight to which the previous wooden ceilings had undergone due to a series of layers that had been added endangered the safety such that the commission for unsafe housing in Rome had declared the unfitness for use of the entire building. The intervention restored the safety of the ceiling without modifying the global stability of the structure since it did not increase the existing load nor did it alter its distribution nor did it vary the stiffness of the ceiling. The load bearing structure in wood which goes back to the 19th century in addition to being made lighter due to the demolition of most of the planking was partially substituted with new wooden elements. In addition the load bearing elements were eliminated by making a new ceiling of mixed steel and reinforced concrete thus a treadable ceiling was made independent of the lower one. The ends of the girders of the new ceiling have steel backing plates wedged into place in reinforced concrete cast during the intervention and anchored to the external walls. Secondary ceilings were made of sheet metal filled with a cast of ready-made reinforced concrete