Most specifications for surface tolerances are ambiguous and perhaps this is why there is no consensus on how to measure for compliance with tolerances. On the other hand there is no standard way of measuring surface deviations, so perhaps that is why specifications are ambiguous. Perhaps measuring floor surface tolerances can be used as a starting point. I'm not sure who developed the method, but it has worked reasonably well for me. One caution: a metal straightedge that we purchased for use with this method was nearly 1/16 inch off from being straight. Accordingly, any standard method that is developed would have to state tolerances on the measuring equipment itself. Is 1/16 inch close enough?

Concrete contractors who may be faced with meeting stringent floor surface tolerances should begin to measure floors they have built. The data gathered should be useful in coming to understanding what tolerances can be met by usual construction methods. The data could also be given to the concreting crews to keep them informed of how well (or badly) they are doing. In addition, the data should be useful in developing techniques for meeting closer tolerance requirements. Finally, the data could be correlated with costs so that contractors can price their work more realistically, particularly when stringent tolerances are specified.