Most—but not all—ceilings are essentially horizontal walls, built using the same materials and methods as their vertical counterparts.
Other than its vertical or horizontal orientation, the main difference between a ceiling and a wall is the size of wood framing members behind the surface. Whereas walls are framed with 2-by-4 or 2-by-6 wall studs, ceilings are framed with joists or rafters that are typically 2 by 8s or larger.
As with walls, by far the most common surface material for ceilings is drywall (also known by its tradename, Sheetrock®). A less common, older and more expensive choice is plaster.
In most homes, ceilings are flat and 8 feet high. That said, departing from the common 8-foot ceiling during construction produces interesting rooms t visual interest and a sense of volume.
Cathedral, beamed, tray, and coffered ceilings are just some of the possibilities, as shown below.