How To Use A Level

How Does a Level Work?

The Process
The Importance of Using a Level
Use a construction level to ensure that your project is straight. Contractors use levels when hanging pictures, window blinds, and doors. If you choose not to use a level, you run the risk of building slanted walls. Most levels are manual and non-powered, while others are laser powered.
The Air Bubble Is Central
Manual levels are anywhere from 6 inches long to 8 feet. Levels contain a liquid-filled tube, encased in plastic or glass. This tube has 2 lines. which separate the tube into three sections. There is an air bubble inside the liquid. When the surface is level, the air bubble in the liquid sits in between the two lines. If the surface is slanted, the bubble will lean to one side of the center or the other. If you lay the level on a surface, such as a shelf, and the air bubble centers between the two lines, you know your surface is level.

The Level Cannot Lie
Water is self-leveling. Bend a plastic tube so both ends are up in the air. Fill it with water. Notice that the water lines are the same level on both sides of the tube, even if one side of the tube extends higher than the other. The water in a level is also self-leveling.

Laser Levels
The laser level works differently than the bubble level. The laser level is battery-operated and levels are checked not by an air bubble, but by a red line. Place the laser level in the area you wish to check such as a window sill, or above a cabinet. Turn the level on. The red light will shine all the way around a radius, in a straight line. Use a pencil to mark the lines, and your project will be completely level and plumb.