I have a concrete stoop about 4'x6' in front of my house that is not level. It has sunk about 2 and a half inches away and to the left of the house. I do not believe it will move any further as all draining problems have been fixed and it has not moved in well over a year. Now this is obviously unsightly and my wife and I have decided we would like to have decking instead. As the concrete stoop is structurally sound with no cracks, I would like to place this decking right on top with sleepers (as seen in this video http://www.thisoldhouse.com/toh/vide...050370,00.html). However, it will require a fair amount of shimming and ripping to get a level plane across the entire thing. My question is, would it be better to keep the stoop unlevel to allow for draining or to encase the stamp in PVC trim and pour concrete to level and put the decking directly on top as in this video? Or do you have any better ideas for the space?
I wouldn't put any structure on this mass of concrete as it's unstable. It will continue to move as it was not put in correctly and the base was inadequate for the mass.
Remove the entire lump and build something stable.