"The mortar used to hold the river rock together can degrade over time to the point where the rocks will fall out or could easily be pulled out."
"If neglected, a distressed river rock foundation not only affects the cosmetic appeal of the home but also puts its residents at great risk.Depending upon the circumstances, a replacement of some or all the unreinforced foundation may be necessary. Usually, homeowners preferred to “sister” the foundation. This preserves the curb appeal of the home. This option is often less costly than a replacement."
added Dutch screaming. Wooden foundation??