Sept. 9- tearing up the floor tiles

Decided to start pulling up the old press down floor tiles yesterday since my wife has her heart set on black and white checkerboard.  Started with a scraper, which was mildly successful- these are all glued down with a heavy black mastic, mind you, not just the normal glue.  I graduated to a flat chisel, not much luck, and then went to the heavy duty industrial scraper- still not making any headway.  I finally went to an air chisel borrowed from my neighbor.  I had better progress, but is was digging into the sub floor as well.  Conclusion for the day- this is NOT going to happen- looks like we install thin hardy backer board and cover it up...call it extra insulation.  2 buckets of sweat, a few more calluses, and a sore elbow...chalk it up to a learning curve.