I've read through the other concrete threads, and I think this warrants a new post.
I'm planning to widen a concrete staircase and landing, 3ft originally, adding 2ft. I'm going to veneer it afterwards with 3cm pavers.
My original plan was 6in 3/4 crushed rock plus 6 in concrete on top, 1/2 in rebar, with 6 in minimum throat on the steps. I was going to dowel into the existing staircase and landing with epoxy. This is all based on rudimentary online investigation.
After digging out the area, I see that the existing staircase and landing, which are totally solid, no cracks, look like half-assed 6-in on grade (meaning 3-5 in actual concrete, 6in throat on the stairs). This is clay soil and I was originally worried about movement.
Given that concrete isn't particularly more expensive than crushed rock, should I just go ahead and pour 8-12 in of concrete? Cost isn't really the issues ($1-200 more in concrete), I want to do a solid job. We are talking about half a yard of concrete, which may increase to 1-2 yards depending on how crazy we go. The short load fee almost covers the extra concrete.
Should I still dowel? I read that doweling such a thin slab could cause spalling. If I do dowel, should I drill 3/4 inch holes and epoxy #5 rebar (5/8in)? Another suggestion I saw was to dig under existing concrete and pour a lip underneath.
I do not want to demo the existing staircase, just trust me on that.
Major issues I see are the clay soil and veneer. I don't want the veneer cracking where the two slabs meet. I could cut control joints into the meeting point, but it would look a bit wonky. Necessary?
In sum, here are my questions:
1) Should I lay down crushed rock or pour double thick on grade?
2) Should I dowel into existing concrete, and if so what specs (rebar, drill, depth)
3) Should I cut control joints into the veneer despite the cosmetic effect?