We're desperate for some advice. We want to build an interlocking retaining wall off of our concrete patio, then extend the concrete patio over to the wall. However, I'm getting different advice on whether or not to just pour the concrete right up to the wall (direct contact) or to put in some sort of expansion joint. Those that say to just pour up against the wall state that the material in the expansion joint will just deteriorate over time and you'll have a gap where water will get in. Others who say pour up to and against the wall say that over time the concrete will pull away from the wall eventually, then you just "fill it" with some sort of gap filler that will then expand and contract. We're so confused. Any advice and photos would be much appreciated. Thank you!!