i am just going to throw out this idea. use it if you want to, throw it out the window if you dont. what abour using 4 1/2" HARD rubber 4" x 4" squares, running the bolts (anchors) through the middle of them. that way, there would be no problems betwwen the floor (any type) and the bottom of the safe. it would also allow air to circulate between the bottom of the safe and the floor. the only problem i can see with this, is it would allow a prying point for burgelars to try to pry the safe out of the floor. if that would even be possible. you might run it by a1abdj to see if it is a good idea or not.