Ladders are typically built from wood, aluminum or fiberglass. The aluminum and fiberglass types provide a lighter, stronger alternative to wooden ladders.
There is no governing body that applies a maximum weight to be used on ladders. Instead, manufacturers state a maximum safe weight dependent on the ladder's material and model. For example, some manufacturers classify their ladders using a color rating system. Red signifies a ladder that is suited for household use (up to about 200 pounds) and yellow is for special duty (up to about 375 pounds).
Although weight is an important factor with ladder safety, there are other factors. A ladder needs to be of a suitable height to ensure the user is not forced to overstretch as well as a suitable material for its use. For example, not using a metal ladder around electrical wires.