The project contains two versions of interior partition, both with an interior step which allows the pipes and plumbing of the new functions to go to the existing shafts. In the first version, the step is necessary in order to allow the sanitary of the small toilet to go under the raised floor to the existing shaft of the kitchen. In the second version, the raised floor is necessary in order to allow the pipes of the new kitchen to go to the existing shaft (where the kitchen was in the initial project).