Q: What are superflat floors?

A: The American Concrete Institute (ACI) website www.concrete.org provides a lot of valuable information on concrete technology and describes superflat floors as follows:

ACI 302.1R-04, “Guide for Concrete Floor and Slab Construction,” defines several classes of floors based on their intended use and the suggested method used for final finishing. Class 9 floors are superflat and require critical surface tolerances.

Defined-traffic superflat floors must support vehicular traffic along paths defined before construction and don’t change during the floor’s life. Narrow aisle distribution centers with high racking systems fall into this category.

Random-traffic superflat floors should support traffic in all directions. They are typically required for gymnasiums, ice rinks, warehouses where air-pallets are used, and television or movie studios where camera dollies must operate.

Superflat floors generally exhibit FF and FL numbers above 50 in the direction of travel. They require specialized construction methods, and cost more to build than floors in standard warehouses, lightly trafficked industrial buildings, or commercial office buildings.