So we purchased a house about 6 months ago. When I went down into the crawl space, it’s clear moisture has caused some issues with bowing with the joists. I will sister those. I’d say it’s a 30’ or so span, with one support in the middle. They look like 2X10. Anyway, this center support holding them up in the center has a “line” in the floor above, feeling raised maybe 1-2”. Enough to trip over. The entire crawl space is lined with sand, and when digging around the foundation in the front, about 4” of top soil then the rest is a gray/black sand, at least the 12-14” that I dug. This foundation is near a river( about 6-7 blocks away from the river bank) and the first house built in this “ plot” of land in 1988. The backside of the house facing the river is normal dirt all around, so it’s extremely confusing. The previous owner said he tried everything and couldn’t keep the water out of the crawl space. I’m going to fix the gutters and install interior French drains. But why on earth would sand be around the foundation? The rest of the yard is dirt. Seems like to me this would allow water to quickly reach the foundation, but I don’t know.