Here is a brief walkthough on ladder. For various tasks, the rigid ladder is the type often used. There are many types of rigid ladders, from the fixed type to the roof ladder type. The fixed ladder is the simplest of these and has no moving parts. Extension ladders are often composed to two ladders where one can retract into the other for easy storage. The ones that form a reverse V are called step ladders. If you need some space to place things like paint cans, you might need a platform ladder, which has a platform at the top. If you must climb up the roof or do some outdoor house painting, you need a roof ladder, which has a hook at the top, for easy latching on the roof. Aluminium is the choice material for various ladders, except those for electrical work.