We were trying to put in some laminate flooring, and as I was vacuuming against the base of the drywall I noticed that dirt kept falling from what looked like inside the wall. The drywall seemed a little flimsy here, so I decided to cut a hole and find out what was behind there.
Our house was built in the 70s, and my wife was searching and found people making suggestions about sand and mortar and things of that nature being used to level the tub, but this is nothing of the sort. It's a very fine dirt - the same that we have in our yard. Inside the hole is the drain for for the tub and the copper water pipes. It smells damp - like under a house. Our home is a one story slab home, and this is a metal tub.
I looked for signs of critters (ants, termites, that sort of thing) but it doesn't look like there are any tunnels. It's very loose dirt. I've probably removed about 2-3 liters of dirt.
Why is this dirt here? Should I put it back? Remove it?