Originally Posted by thinktankair
I have a sagging floor edge next to the toilet of my 1961
bambi. I have removed the kitchen and I can shim the floor against the top of the black tank. Is the top of the tank tough? Can it take the pressure of the shims holding up the edge of the floor. Thank you!!
The top of the tank is not designed to be load-bearing. You're much better off shimming against a framing member, if there's some way to do it. I would only shim against the tank if your shim is actually a metal plate longer than the top of the tankó and more rigid than the top of the tankó so that the shim is supported on the edges of the tank, not the center of it.