Our existing courtyard concrete patio looks pretty wore: discolored/peeling surface, but no big cracks other than a few hairline.

Another problem is it poured too high: it is against the base of the house on 3 sides, and on one side it levels with the floor of the house. It seems there were water damage on the wall and floor from rain water seep in (this was before we become the owner)

We want to fix this by cut out a strip along the base of the house, to expose the dirt so we can install a drainage.

We also want to improve the look of the patio by wet-laid bluestones on top of the concrete (since we cut off the highest part of concrete away from the base of the house, the increased height of the stone is not a problem)

- Do we need to worry about concrete shift or cracking later? (we don't know if the concrete is enforced with wired-mesh, but so far there is no major cracking).
- Will cutting a section along the base could cause concrete to shift ?
- What kind of mortar to use? Should we use thinset?
- The concrete pad has expansion joints; what we do with them? can we mortar and lay the stone over them?
- If the shift/cracking are real problem, should we dry-lay the stone with a layer of sand bed?

We live in central California, so the weather is mild.

thanks for your advice.

Steve