What do floor flatness numbers mean?
What do floor flatness numbers mean? Floor Flatness (FF): The FF number essentially tells you how flat your concrete floor is. Bumps and grooves cause your Floor Flatness numbers to drop. Higher F-numbers equal flatter floors. Floor Levelness (FL): The FL number indicates if you have any tilts or pitches in the slab. What are F-numbers in concrete? The American Concrete Institute has adopted F-Numbers as its standard for the specification and measurement of concrete slab flatness and levelness. Ff, or "flatness F-Number," defines the maximum floor curvature allowed over 24" (600 mm) computed on the basis of successive 12"...