The crawl space is a dark, dank, creepy, subterranean hole no one wants to venture into. That said, there are certain trades that must traverse the icky and go below. When considering an inspector it's real important that he/she does a thorough inspection of the crawl space.
Pictured here is a crawl space in a 1930s home. There are several issues here but the main concern is the red posts. They are supporting horizontal boards that are in turn supporting a concrete slab. The joists are cut and a 2x installed to "cap" the joists. The posts are also resting on concrete blocks that are sitting on dirt mounds.
So what's the problem?
First of all the floor system isn't sized for an eight inch slab. The horizontal boards are "falling" to the outside wall and so is the concrete. This is putting undue strain on the floor system, outside wall and foundation.
The joists, when cut in the middle of a span, have to have a properly sized beam installed and that beam must transfer the weight to some point.
Sitting support posts loosely on blocks that are sitting on dirt is a huge problem as well. Any shift in the soil beneath could cause the floor to collapse. There should be footers poured at the proper depth for your climatic zone and the posts (properly sized) should be fastened at the top and bottom.
The issues found in this crawl space are numerous and in no way diagnosable from the top. In other words, you wouldn't know these problems existed if you weren't in the crawl space.
When I found what you see in the picture it ended up being an expensive fix for the owner of the property...but a necessary one.
