Finished Concrete Floor Flatness

The fallacy of the straightedge method was the location of the measurement.

Finished concrete floor flatness.

This applies to floors that will receive finishes such as wood quarry tile carpet or sheet vinyl products. Ff flatness is most affected by the finishing operation. Common tolerances were 1 8 inch or 1 4 inch in 10 feet. Material tolerances are in section 2 including the location tolerance for reinforcing bars which varies depending on the thickness of the concrete member.

Rejecting floors based on one sample measurement line concrete international jul pp. 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. Due to concrete shrinkage and slab curling ff fl numbers diminish with time. Tom klemens the dipstick tool is the typical measurement taken for flatness the morning after concrete is placed.

The ffnumber relates to the rate of change of the elevation of a concrete floor over a 12 interval. For the concrete contractor flatness is specified as an ff number and levelness as an fl number. Aci staff 2008 concrete q a. Fl levelness is most affected by forming and strike off.

American concrete institute aci 301 16 specifications for structural concrete. Aci 117 begins by defining what the tolerances mean in terms of such things as bowing deviation flatness and levelness and provides drawings to help explain these terms. Specifically joints and cracks curl making the floor less flat with the passage of time. Both numbers are dimensionless and the higher the number the more accurate the floor construction.

This method worked quite well for decades. Concrete floor slab flatness and levelness traditionally allowable tolerances of concrete floor slabs were determined by checking the slab surface with a 10 foot straightedge. Floor flatness and levelness testing the complete. This was measured by laying a 10 foot straightedge on the finished floor and measuring the greatest gap below the straightedge.

History of concrete floor flatness and floor levelness traditionally concrete floors were specified to have a deviation of less than 1 8 over 10 feet. Concrete contractor pours the concrete and finishes it to the specified floor flatness requirement as stated in aci 117 specification for tolerances for concrete construction and materials the f.