What is a Plumb Bob
Definition of Plumb Bob in Construction
A plumb bob is a tool that will allow an accurate representation of the plumb orientation of a structural or other construction element. To be plumb is to form a right angle to the horizontal surface of a floor, ceiling, or other element. A plumb bob is basically a free hanging weight, which is shaped to allow the center of gravity to align with the center of the weight. By tying a string to the end of the weight, it will hang vertical, or plumb, based upon the gravity pull of the earth. The use of a plumb bob, to establish the correct position as well as the accuracy of a vertical structural member is critically important to allow the correct positioning of the loading force in a vertical direction. This vertical loading is important to eliminate any twisting, moment development, or lateral forces on a structural element that is intended to only function in a vertical plumb orientation.