If you need a Ladders for a particular task, you might want to know more about ladders in general. This may help in your choosing the right ladder for the job. For various tasks, the rigid ladder is the type often used. Rigid ladders have many kinds – fixed, extension, step, platform step, and roof. The most basic of these is the fixed ladder; it has no moving parts. Extension ladders are often composed to two ladders where one can retract into the other for easy storage. Joined by a hinge at the top, and often forming an inverted V, are step ladders. A platform step ladder has a platform at the top. If you need to 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.