Thousands of years ago the Chinese princes would order their builders to test the ground of a new building site before work commenced to see that it corresponded to the requirements for healthy living. We do not know exactly how they went about it, but we can see from old records that the order was carried out each time. In order to provide the healthiest possible conditions, it is important to consider whether a house is to be built on rock or gravel, on clay or marshy ground, whether the foundation is laid in wet earth with a high groundwater level or whether the ground is dry. One might have no other choice but to accept the plot of land that does not have the best conditions, in which case it is up to the builders to minimise the existing deficiencies and disadvantages by means of technical devices, perhaps by drainage and insulation or lagging.
You may have never given any thought to the importance of checking a building site from the standpoint of whether it provides a basis for healthy living.