Hello,

I'm redoing my front porch stairs, the old stringers were encased in
the concrete bottom step, not a good thing. I want to bolt a board to
the top of the concrete and notch the bottom of the stringers to meet
the board.

So I need to somewhat enlarge the step. It is about 66" L x 16" W x
12" D. The back side of the step is all rough concrete with large
aggregate. The top of the step is a greyish material without
aggregate; it is somewhat chipped and not particularly flat, so it
could use redoing. Here's the procedure I've come up with, I'm
looking for any comments or suggestions:

Remove any loose soil behind the step. Clean the backside of the step
with a hose and brush. Drill 4 holes 6" deep into the back side of the
step and epoxy in some 9" #4 rebar stubs projecting out 3". Form up
to extend the step 5" (providing 2" cover on the rebar ends). Mix and
pour 4-5 0.45 ft^3 bags of sacked concrete, poking it into all the
voids. Leave the new concrete about 1" below the finish surface and
allow to cure a day. Chisel the the top of the old step to roughen it
up and remove 1/2" to 1" of material. Mix some non-shrink grout (e.g.
CementAll) and pour a smooth finish surface at the desired pitch and
elevation.

Thanks, Wayne