Term:Floor Flatness [ff]

Floor flatness is a measurement taken that reflects the flatness of a concrete floor after it’s pour. The technical way of measuring floor flatness is as follows:

“Floor flatness (F_F) controls the bumpiness of the floor surface and is primarily affected by the finishing operations after screeding, including restraightening and power floating. Essentially, F_F numbers evaluate the elevation differences along a sample line at one-foot intervals. F numbers extend from zero to infinity so the higher the F number, the flatter the floor.”

Flatness should be measured as soon as possible, preferably within 24-hours after concrete placement but no later than 72 hours.