How to Install a Drop Ceiling's Outside Edge

Set up a stepladder near one wall of the room. Make sure the stepladder allows you to reach the required height without standing above the second rung from the top of the ladder. Place the end of the tape measure on the floor and pull the tape measure up the wall. Place a pencil mark at the height of the ceiling. Ensure you have at least 4 inches of open space between the line and the structural components of your house.

Align the bottom edge of a 4-foot level with the pencil mark. Adjust the level until the air bubble -- in the horizontal vial -- sits evenly between the two marked vial lines. Draw a pencil line along the bottom of the level. Move along all walls until you have one continuous line around the room.

Locate the wall studs of each wall with a stud finder. Mark each stud location with a vertical pencil mark that intersects the height line you made earlier.

Measure in 12 inches from one end of wall angle, place a pencil mark at the location and cut the angle at the mark with a pair of aviation snips. Bend the wall angle at the cut line. Make sure to only cut through one side of the wall angle.

Align the top of the cut angle with the line you made with the 4-foot level. Run one screw into each stud -- located behind the wall angle -- with a screw gun to hold the wall angle tight to the wall. Push the end of a second piece of wall angle to the end of the installed section of wall angle. Run one screw into each marked stud to secure the second piece of wall angle. Continue the process until all wall angles are installed on the wall.