InterNACHI Home Inspector Practice Exam 2026 – Comprehensive Test Prep

The "4-to-1 Rule" for ladder safety provides a simple guideline to ensure that ladders are set up at a safe angle. According to this rule, for every 4 feet of vertical height that the ladder reaches, the base of the ladder should be positioned 1 foot away from the wall or structure it leans against. This creates a safe and stable base, significantly reducing the risk of the ladder tipping over or becoming unstable during use.

Using this rule helps to ensure that the ladder is at an appropriate angle (approximately 75 degrees), allowing for safety while climbing and working. Thus, moving the base of the ladder out 1 foot for every 4 feet in height is the correct application of the "4-to-1 Rule."