Falling Water is not built on solid ground!It stretches over a 30' waterfall! So it was very hard to build and there were a lot of technical problems with the support of the structure.The Kaufmann family and Wrights crew were worried there was not enough support for the house.And Wright refused offers to add steel in the floor to add more support.So there were a lot of arguments and the Kaufmann's almost didn't go through with building !