About 600 gallon, 2300 Liters tank for water to heat house, solar and some wood.
Being uninsulated, just warming up and cooling down with the humidity going up and down over the years would cause the flaking. Soaking water or hard freeze would do it faster but expansion and contraction will do it. I can till the difference the bead board insulation is making in my basement. No chill or breeze along the finished part. Get some disposable gloves to wear while using the great stuff to seal.
I plan to go around the out side of my foundation this summer with foam. Also enclosing my front porch. It's crawl space has no real separation from my basement.