In order to do a job safely you need the perfect size extension ladder. In order to get the perfect size ladder you need to get one that has more length then the highest point of where you will be reaching. The ladders are sold in increments of the even foot measurement, including the 24 foot extension ladder and the 28 foot extension ladder. But when purchasing a ladder be sure to allow for the overlap of the extensions because when extended it is not the actual length of each section of the ladder. For example, if you were to purchase a sixteen foot ladder, it would come in two eight foot sections. After they are mated together, they are overlapping so therefore it is not the actual 16 foot but your maximum reach would be 15 foot.
The same would be the case for a 24 foot ladder. It would have a maximum each on 23 foot and the highest point that the ladder will touch is 13 – 17 foot. Then figuring on the 2 foot extension, you would only have a 27 foot maximum reach with the highest point the ladder would touch as 17-21 foot. So be extra careful in figuring the size that you will need.
These figures were based on a 5’6″ person that has a vertical reach of 12″, so be careful to put this into consideration also when figuring your proper and safe size. These figures are also based on the support points for the overlap section, the angle of the ladder, or about a three foot extension above the roof line. There is a lot to consider before deciding on the proper size of extension ladder. It is not only to do the proper job but to keep you safe also. Another safety guideline is considering that your ladder needs to be one foot away from a building for every four feet you need to climb up the ladder.
These ladders have two or more sections that travel in brackets or guides that allow the length to be adjusted. These extension ladders are only intended to be used by one person at a time. It needs also to be tied down at the top level before climbing on it and the extension ladders is still very easy to tip sideways or cause the base to slide out.
Ropes and pulley systems are incorporated into the extension ladders to help the user to adjust the height. They help to engage the rung locks into proper placement. Another safety precaution is to make sure that the pulley rope is tracking correctly.