Here is a brief guide on ladders. The all-around ladder is the rigid ladder, and it’s often used for many tasks. Rigid ladders come in many varieties, from the fixed to the roof ladders. The fixed ladder is the most basic, and 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 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.