Ventilation device for house building

The utility model discloses a ventilation device for house building, which comprises a shell, a support is welded and fixed on the lower surface of the shell, a motor is arranged in the shell through a connecting frame, the end part of the motor is rotatably connected with ventilation fan blades, a mounting groove is arranged at the edge of the end part of the shell, and the ventilation fan blades are arranged in the mounting groove. A protective net is mounted in the mounting groove; the clamping holes are designed in the edge of the protective net, the clamping rods are designed at the inner edge of the mounting groove, the protective net can be closed in the mounting groove by penetrating the clamping rods into the clamping holes, and the ends of the friction plates are extruded on the surfaces of the ends of the clamping holes under the action of deformation of the springs; fastening of the friction plate is enhanced by screwing the shifting plate, so that fastening is enhanced after the protective net is