Floor Flatness and Levelness Testing

Floor flatness (FF) can be associated with the bumpiness of the floor surface and is primarily affected by the finishing operations. “FF” numbers extend from zero to infinity so the higher the FF number, the flatter the floor.

Floor levelness (FL) controls the departure of the floor surface from the specified slope or plane of the surface. “FL” numbers evaluate the elevation differences along a sample line at certain intervals. The higher the FL number, the more level the floor is considered.

Floor flatness and levelness testing should be performed per ASTM E 1155 “Standard Test Method for Determining FF Floor Flatness and FL Floor Levelness Numbers.” Flatness and levelness readings should be measured as soon as possible, preferably within 24-hours after concrete placement. With the passage of time, joints and cracks curl making the floor less flat. Typically flatness and levelness testing is performed to verify the contractors work has been performed to specification. If you are unable to make a measurement within the specified time frame, FF and FL numbers may not represent the true performance of work.

Shield offers specialty testing on floor flatness and floor levelness. Our technicians and engineers are trained to evaluate flatness and levelness for slabs-on-ground and suspended slab surfaces.