I need help for my elderly neighbor lady. She has existing wood panel siding on the exterior of her house. She would like her house to look nicer, and talked to a contractor about adding stone veneer to some areas. He told her that the wood siding doesn't need to be removed or any prep done besides a scratch coat applied directly to the siding first.

We don't know anything about construction, but putting mortar directly on wood siding doesn't seem right to me or my neighbor. I tried looking it up online but didn't see a definite answer. I did read that using house wrap is recommended on top of wood before installing stone.

Is the contractor right? Or does the siding need to be removed/house wrap used? Thanks in advance.