Floating support post in crawl space

[james]

While inspecting newly laid vapor barrier, I noticed one of the support post is floating -- there is a gap between the bottom of the post and the concrete base.

Here are some photos of this:

The other posts all have a piece of black tar(?) sheet (about 2mm thick) between the bottom of the post and the concrete. Perhaps the workers accidentally pulled out that black sheet while removing the old vapor barrier.

What is that black sheet called? I think I need to buy one and quickly insert it back into the gap before gravity pull the joist and the post down. I believe this black sheet is to prevent moisture from wicking up into the wooden post

[jameswaters]

Good grief, first a gas leak, now this..... I think it's time you get a new house :)

Seriously, drive some cedar shingles under the post and dont worry about it anymore. It looks like the post is only a quarter inch from the cement at most and the wood looks ok. You could also find a piece of steel of the same thickness to drive under it. (Paint the steel to prevent rusting).

[tbasc]

You don't specify climate or ground condition. In South Carolina, we recommend sealing the vapor barrier to the walls. As for the post, the cedar shingles will shim the post tight, so that it actually supports the load from above. Cedar will resist rot if there is condensation or moisture moving up through the concrete. As a cautious person, I would add a sheet of poly against the concrete to stop moisture. T

[aemeijers]

Unless your crawlspace is damp, I don't think it matters much. Anything you have laying around that is not too compressible and is waterproof and unappetizing to termites should work. Make sure post hasn't sunk- even gorilla workers would have trouble pulling something out from under a post that was carrying a load.