So, it is a terrible picture. This is a picture taken under the house. Here we are looking at the front Southeastern corner of the foundation. Visible, aside from the glare of the sun, is the cinderblock and wood beams. Between the beams and block we placed tar paper to help mitigate the little bit of moisture that could wick up the block and into the wood. We also put a fair amount of sand under the house to act as additional thermal mass. We had the sand and it seemed like a reasonable place to put it. It also makes crawling under the house more comfortable than if it was bare gravel. We will place a vapor barrier over the sand. Lastly, We reinforced the concrete foundation with 2 inch tubular steel. We had an old carport that was destroyed in a tornado so we used the steel to angel brace the foundation and tie it all together. We also used rebar in the foundation but thought the added steel would be a nice addition.
Here is a picture of the house prior to the second floor being studded and roofed.