Any house built on more than one level has at least one staircase that serves as its vertical thoroughfare. There are, of course, many different kinds of staircases, differing by their materials, construction methods, general shape, design, and a number of other features.

In most situations, a staircase is an integral part of the home’s design and style. Stairs may be steep or gradual, narrow or wide, purely functional or grand and showy. Some are built in place by woodworkers, finish carpenters, or stairmakers; others are factory manufactured, shipped to a building site, and installed by carpenters.

A stair’s design is heavily affected by its function. An entry stairway that handles all up-and-down foot traffic and is placed in a highly visible location is bound to be much more grand than a stairway to a hardly-ever-used basement or where economy of space is imperative.

Regardless of type, all stairs have the same fundamental parts, as shown here. It is how these parts are built and combined that gives a stairway its style and individuality. Of course, not all stairways have all of these parts—for example, some stairways have open risers.

Stairs are built according to basic rules and principles intended to make them safe to use. These rules, governed by building codes, stipulate the permissible heights of risers, depth and width of treads, placement of handrails, and similar concerns.