I have installed Wonderboard on the 3 walls surrounding a coal fired stove. My plans are to install rock veneer over the Wonderboard. The distributor was not sure if I could run mortor over the Wonderboard (concrete board) or if I needed to screen. The rock is going to run floor to ceiling 8'. The rock veneer is apparently placed in one "rock" at a time in mortor directly against the firm surface. Any suggestions or experience with these products?