What is a ladder I-beam usually made of?

A ladder I-beam is typically made from fiberglass. This material is known for being lightweight yet strong, providing the necessary support and durability for firefighters while being less prone to corrosion compared to metal. Fiberglass also has the advantage of being non-conductive, which is crucial when working around electrical hazards during firefighting operations.

While steel and stainless steel are indeed used in various ladder components, they are not used for I-beams specifically in this context, as fiberglass is preferred due to its specific properties that enhance safety and ease of use. Wood, though historically used in the construction of ladders, is not suitable for modern I-beam construction due to its susceptibility to weathering, rot, and lack of uniform strength when compared to fiberglass.