Here are the Top 10 reasons a retaining wall fails — and how to avoid every one of them. 1️⃣ Poor base prep. Most walls fail from the ground up. If the base isn’t dug to solid soil or doesn’t use a compacted #57 stone foundation, it’ll settle unevenly and lean. 2️⃣ No buried first course. That first course below grade anchors the wall. If it’s sitting on top of the ground instead of in it, the wall has nothing holding it back and eventually kicks forward. 3️⃣ Not enough drainage. Water is the ma