I am currently in the planning phase for two bathroom remodels on the second floor of my house that was built circa 1910. In addition to many other efforts, I am redoing the tile floors. The tiles appear to be set directly into a 4" thick concrete slab. I've been able to knock a few of the tiles loose with just a hammer and chisel but others just fractured with the bases remaining attached to the concrete. I will likely rent a chipping hammer to get down into the surface of the concrete but now I am questioning whether or not to just take the whole concrete slab out as well. Is this advisable to remove with a sledge? The plumbing (to radiators, toilet, sinks etc) running through the concrete will be easier to deal with if I can create a new subfloor. Also, I will be alleviating thousands of pounds of load from the joists which have bowed over all the years (probably due to creep from exposure to leaks in the bathrooms). What I definitely don't want to do is destroy the plumbing that I wish to keep in place.