I have a cement driveway with a retaining wall. The drive has sunk about 5" in one area about 15'/15'. The caulking or sealer has worn over the last 7 years and water can run down where the drive meets the wall. I would like to get a fair estimate on the cost or could I tackle the job myself? I would need a good reference on how to do the job and would it be possible for me to send digital pictures to someone to tell me what I need to do.