How to Check the Level for a Plumb

Things You'll Need

  • Carpenter's level

  • Level clamp

  • Plumb bob

A level can check for plumb.

Determining plumb, level and square are crucial when building and remodeling. If these elements are not correct, then the best tools and designs will not be able to rectify a structure put together without these principals. Plumb means true compared with a vertical plane, and level means true compared with a horizontal plane. An object or room is square when a plumbed object/wall is intersected to a level object/wall, creating a 90 degree angle. Two tools can be used to check the plumb of an object.

Step 1

Check that the vial is set correctly. Position the level, also known as a spirit level, against a vertical surface whether or not you suspect the surface is plumb. Note the position of the liquid in the level bubble. Turn the level around, end for end, so that it is in the opposite position from the original position. When the bubble goes back to the same position as when you checked it in its original position, then the vial is correctly set.

Step 2

Attach a level clamp tightly to a vertical object or post to set for plumb. If you are checking for plumb on a column or a post, which is more than 4 feet long, you will need to use a 4-foot long level. Levels can be made with a plastic, wood or metal frame.

Step 3

Examine the liquid in the glass bubble in the center of the level. If it is plumb, the liquid should be straight across in the bubble and not on any kind of angle at all. It is important to be completely accurate. If the plumb is off, even by the smallest amount, it could compound problems as you continue with your remodeling project.

Step 4

Check for plumb on two adjacent sides of the object to ensure accuracy.

Step 5

Suspend a plumb bob to recheck for plumb when there is a concern about a vertical object such as a column shifting position during remodeling. A plumb bob is a pointed brass or steel weight that has a line attached to it. Suspend the line beside the surface you are checking from a height and drop the plumb bob toward the floor. When the plumb bob is still, use the line to determine the vertical alignment of the object you are checking. If it is plumb, then the line should be exactly parallel to the wall or object.


Alternatively, use what is known as a torpedo level to check for plumb. The torpedo level is a shorter version of a carpenter's level, usually about 8 or 9 inches long, and it is handy to use in small spaces. The torpedo level consists of three bubble vials used to determine plumb, level and a 45 degree angle.

references & resources