Well hi Obed and all, Thank you all for the support and concern. I have been reading along as posts came in and initially I was taken aback and very outraged at having been so poorly served by a contractor who had always previously treated us very well. I was angry at being taken advantage of when all I wanted was to get my barn ready for moving in my shop equipment and tools. I called our lawyer, who advised me to contact the town's building inspector as an independent and impartial opinion and observer. We eventually had both the original contractor, and our town's building/code inspector (CEO) up separately to look at the floor, and while they did see the uneveness, they both independently measured it in several areas using both long and short levels (3' & 6' I think) and again independently came up with a measurement of something like <3/16" variation over 6', which the CEO assured us was to code and a very normal amd reasonable amount of variation. What they figured caused the wavy appearance was the combination of a very low and very bright (1000 watt halogen) light source and incompletely cured concrete (because of the cold weather in the weeks since it was poored). Nonetheless, the contractor waived the $175 we still owed him for supplemental concrete needed to finish the pour because he felt that as repeat customers, who have referred others to him (he did the pad fill and grading for our building site and did an excellent job relatively inexpensively), he wanted us to be completely happy and satisfied. BTW, it turns out that the floor WAS power-floated and ironically some part of the visible "gradient markings" were swirls left over from that. We have since powerswept the floor, washed it, and sealed it with Foundation Armour S2000 penetrating Concrete Sealer and Radon reducer. There were a few very minor areas of pooling when the floor was wet, but nothing that was out of the ordinary or dramatic. Thanks again for all the thought and concern expressed on our behalf. Thomas.