The tunnel or multi-chambered greenhouse consists of the roof structure, each formed by a post (1), a cross beam (2) and two arcuate sections, forming the roof covering. Purlins (5) are linked to form two consecutive roofs and gutters (6) link together several consecutive roofs. The plastics film cover (7) is supported on the purlins (5) and is constructed of two parts (8,9), each with a fixed end, linked solidly to the gutters (6). The other end is mobile and is fixed to a support beam (10, 11), which can be displaced along the arcs (3,4), from the roof line (12) to the gutters (6). The positional controls can be either manual or automatic.
