Covering cement steps w/flagstone or slate

by Tracy Hager
(Portalnd, Oregon)

Hi Hans:
My home bulit 1907(portland ore) I have cement steps (4) going up to front porch which is wooden (5 x 5).
Last winter lots of ice on cement stairs I put rock salt on stairs now they are crumbling a little. the material they used back then has lots of small pebles rocks. So anyway i want to cover these existing stairs with flagstone/slate etc. QUESTION; Do I need to completely remove existing stairs? Or can I just scrape away at crumbling area and place a layer of fresh cement /mortar(thinset ???) and continue laying flagstone/slate as described in your instructions. I have experience laying flagstone path in my backyard making cement slab then laying flagstone etc.
thanks Tracy