Can you get some pictures up?
I remember those, although I don't remember them in residential. Once you've determined how much needs to be removed, you can use a die grinder with a reinforced cut-off disc. I strongly recommend a full face shield.
your oscillator with a metal blade may cut it or go with a grinder with a metal cut off wheel and cut a small 1/8" above the flooring thickness or even a tight cut if you can manage it. way better to have a tight cut than to caulk it later....Thought I would give this thread a little bump for some more ideas.
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