I have an old house, nearly 100 yrs, with a foundation, combination concrete block, wood, and support posts throughout the floor area- all very solid and dry. The crawl space is dry sand. I have recently replaced rotten wood under one outer wall with solid posts on concrete slabs. The strength for this wall has come frome two sections I bumped out some years ago. I have made sure that water run-off will not affect any other wooden areas. Ground drainage in this area is fabulous. Construction includes a very large log as a horizontal beam. I have lived here 30 yrs and nothing has ever moved. I am trying to sell and prospective buyers are scared off by the crawl space appearance. Any thoughts on how durable this house is in the forseeable future?