Abstract: Safety scaffold or platform foldable structures for ladders are disclosed. The scaffold structure embodies an elongated expandable scaffold floor section which is removably connected to two spaced apart upstanding ladders. Male and female floor sections are expanded to the desired length and locked in place by a locking pin. Spaced apart double hook hinges are releasably secured to one rung on each ladder. Wedge mechanisms work in conjunction with the hook hinges engaging the ladder rails to secure the scaffold structure in the horizontal open working position. The platform structure in the form of the letter H is removably connected to two adjacent rungs of a single ladder. The pair of hook arms hook around the upper rung and a pair of bottom arms support the structure on the lower rung. Descending wedge mechanisms engage the ladder rails in supporting the platform structure in the horizontal open working position.