Re: Clay Tile Foundation
there are established ASTM standards for structural terra cotta blocks, either for those exposed to weather or not. I would rather see the block used on top of a concrete foundation (I have worked extensively on two such houses, both built around 1910). I would worry about any situations where they are below grade outside, and stay wet; we all know what happens to terra cotta pots left outside for the winter. You want to make certain that your gutters and drainage are impeccable. Be wary of any products or materials that would cause moisture to become trapped in the blocks.
Remove not the ancient landmark, which your fathers have set.