A joist is a horizontal member that supports a floor or ceiling. Foundations support joists, as do wall frames and beams. Think of joists as being laid out like ribs in a human body. Joists are made of wood, steel or engineered wood. In some builds, a joist has a cross section and in others, steel joists with different shapes are utilized. The type of joists found in your floor or ceiling will depend on the structure and build of your particular home.


It is important to consider that joists will be supporting a load over an extended period of time, often decades. They must be made of the right material, and they must be installed properly. In newer home builds, traditional wooden joists may not be the correct choice. Often, a builder will choose an engineered joist because of its durability and strength.


There are a variety of joists, including single floor, double floor and binding. When joists are left exposed in a floor, it is called articulated or naked flooring. These joists may be sanded smooth or left beaded. In the cases of naked flooring, the way the joists are finished or left unfinished is often dictated by the tastes of the home owner.

If you have questions related to joists or any other aspect of your new home’s construction, speak with an experienced home designer. A designer can explain more about how joists will help support your home and how long you can expect them to last depending on the material they are made with.