Raised Floor

A raised floor (also raised flooring) or access floor(ing) (also raised access computer floor) are types of floor that provide an elevated structural floor above a solid substrate (often a concrete slab) to create a hidden void for the passage of mechanical and electrical services. They are widely used in modern office buildings, and in specialized areas such as command centers, IT data centers and computer rooms where there is a requirement to route mechanical services and cables, wiring, and electrical supply. Raised/Access Flooring can be installed at varying heights from 2 inches (51 mm) to heights above 4 feet (1,200 mm) to suit services that may be accommodated beneath. Additional structural support and lighting are often provided when a floor is raised enough for a person to crawl or even walk beneath.

In the U.S., underfloor air distribution is becoming a more common way to cool a building by using the void below the raised floor as a plenum chamber to distribute conditioned air, as has been done in Europe since the 1970s.