the side rails the ladder guard 100 is preferably 13 inches wide some older wooden ladders are as wide as 16 inches but only at the base which is lower than the ladder guard would normally be mounted in testing the device the inventor has found that children were unable to ascend a ladder with as much as one inch of rung space thus even the widest ladders in common use cannot be ascended with the ladder guard 100 installed referring next to fig3 the ladder guard 100 is shown mounted on the narrow ladder 64 the ladder guard 100 completely overlaps the side rails 65 of the narrow ladder 64 thereby preventing ascension the preferable sheet width d71 of the ladder guard 10 is 13 inches most recreational vehicles have a ladder width of 13 inches the preferable tongue width d72 is 8 inches this allows the ladder guard to fit ladders with inside rails as narrow as 8 inches the length d70 ranges from 22 inches to 29 inches when fully extended referring next to fig4 a cross sectional side view of the ladder guard 10 is shown top angled plate 24 and bottom angled plate 26 engage the rungs 620 of wide ladder 600 the padlock.