Abstract: A supporting framework is formed by an arrangement including closed longitudinal frames (3,9,12,14) integral with base beams (16A) forming support and sliding runners, with a floor panel (9), a roof panel (14), and end walls (10,12), all defining a usable space. Along lower longitudinal axes are pivoted, on each side, panels (40) foldable for lowering and panels (34) foldable for raising, which are adapted to form respectively a flooring and a roofing, together with panels (44) adapted to form longitudinal vertical walls for additional spaces, which are adapted to be supported by adjustable legs (24) on the ground. To the end walls (10,12) are vertically pivoted panels (30) adapted to open out to form vertical walls completing the additional spaces.