Abstract: A mechanism for guiding roll up doors made from a foldable sheet. A longitudinally extending wall of the foldable sheet is secured to a fixed structure and two longitudinally extending lateral walls extend perpendicularly to form another two reversible folds resulting in two longitudinally extending inner walls at a spaced apart and parallel relationship with the two lateral walls. From one of these inner walls, a longitudinal wind bar extends at a predetermined cooperative angle. Upon the application of a wind load to the door slats, the load is transmitted to the foldable sheet guiding assembly from the slats directly and through the wind lock assembly through at least four contact points. The laterally articulated door slats include longitudinal hook portions or wind lock assemblies that slidably coact with the wind bar to keep the slat in place.