Can you put these mats over existing thin interlocking mats? Do they need glue or double side tape to be set in place?

Our 3/4" Extreme Mats can be installed over any hard, flat surface, so you can install these mats over other floors with ease. These rubber mats don't need to be glued or taped to stay in place. The weight of the mats will help to keep the mats in place while in use. If for some reason, there were movement with certain exercises, we would then recommend using some double sided tape or glue.