Coffered Ceiling
The coffered ceiling is adaptable to a variety of treatments by changing the number of steps and by adding moldings. You'll build each step from 2x lumber, which measures 1-1/2 inches thick, plus a layer of 1/2-inch drywall. As a result, each step adds 2 inches of thickness.
A room with a standard 8-foot ceiling can easily tolerate a 2-inch loss of headroom in the name of style. A second layer in that room isn't out of the question. But if you want to add a third step, your original ceiling height should be at least 8-1/2 feet to avoid a claustrophobic feeling.
The two-step ceiling has a 2x4 strip above the second strip. This additional lumber width provides a nailing surface if you want to add moldings. Cove, crown, or bed moldings are three possibilities. The addition of moldings has two positive benefits: The millwork adds style and interest, and you don't need to be as precise with your drywall work when the inside corner is covered.