A newel, also called a central pole or support column, is the central supporting pillar of a staircase. It can also (usually as "newel post") refer to an upright post that supports the handrail of a stair banister. In stairs having straight flights it is the principal post at the foot of the staircase, but the term can also be used for the intermediate posts on landings and at the top of a staircase. Although its primary purpose is structural, newels have long been adorned with decorative trim and designed with different architectural styles.
Newels are sometimes called solid newels in distinction from hollow newels due to varying techniques of construction. Newel posts turned on a lathe are solid pieces that can be highly decorative, they typically need to be fixed to a square newel base for installation. Hollow newels are known more accurately as box newel posts. In historic homes, it is believed that the house plans were placed in the newel upon completion of the house before the newel was capped.
A loose ball cap finial on the newel post at the base of the stairway is a plot device in the 1946 classic It's a Wonderful Life. The same is used in jest in the 1989 film Christmas Vacation, in which the Clark Griswold character, in an emotional "melt down," cuts a loose finial off of a newel post with a chainsaw. He casually exclaims, "Fixed the newel post!" and carries on.
It is also important to consider the methods used to fix a newel post to the floor. The most common method is to use a newel post fastener which secures a newel post to a timber joist through either concrete or wooden flooring.
A cast iron spiral staircase clearly showing the central newel post that supports the treads, risers and balustrade.
spiral staircase at Fort Benjamin Hawkins