A line level is a tool you can use to project a straight line on a wall, floor or ceiling. It creates a laser line, usually about 10 feet long, at the same level around a room. Use this line to ensure a straight row of pictures, even paint borders and level hanging projects such as curtain rods or shelving.
Step One
Choose the placement of your project and align the level at the desired height. Ensure your wall is free of any frames or window coverings, and pull furniture away from the wall so you don't distort your laser line.
Step Two
Hold the line level against the wall and point the laser end in the direction of your project. Note the two levels, one vertical and one horizontal on your tool. Center the bubble of the vertical level between the two lines in the middle of the window for wall projects, and line up the bubble in the horizontal window for a line on the floor or ceiling.
Step Three
Turn on the laser and attach the line level to the wall. Be sure you keep the bubble between the lines so the laser line stays straight. Mark your attachment placements along the line projected on the wall.