how far to extend an extension ladder
supporting ladders should be set at a 4:1 ratio (see Figure 1) from the foot to the top support. Each section of a multi-section ladder must overlap the adjacent section by at least 3 feet for. ladders up to 36 feet and 4 feet for 40 feet or longer extension ladders. For example, a 24-foot extension ladder will. consist of two sections each 12 feet long, but the maximum extended length will be 21 feet, because the sections over-. lap by no less than 1Â½ feet when the ladder is at maximum extension.