Flat roof structure, Span: 4.2M, Section :3.8M; Wind load: 0.75 KN/M2 The frame works structure is consisting of main poles,self-made specialmetal profiels,O shape PP pressing bar and various joints.It is prefabricatedstructure without any welding point. All material is hot galvanized with zinc cover 275g/M2; Covering is insect net or shade net with anti-UV; Double insect insulated doors.