Hoping someone can help with this question. I am installing new tile in an existing bathroom. The existing floor is tile over a 2 inch mortar bed. Should I just install the new tile on top of the old? Seems to me that since the old tile comes up fairly easily I could use the old mortar bed for a base. Any reason not to? It seems very solid. Removing it would be a big job not to mention installing a new base of dura-rock. Thanks for any advice.