Step 2: Cement pier at bottom of hole.
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Mix up some quick-setting cement and spread it on a 16'' x 16'' square concrete paver with the corners chipped off (so the outer barrel will not touch it). Place this in the hole with the cement down to get a good contact with the dirt. Once it is firmly in place and level, cement a 12'' diameter round concrete paver on top of it. Repeat with another round concrete paver on top of that one. Spread the leftover cement into the cracks between the two round pavers. It should dry in about 5-10 minutes. If installing a drainage trench, lay the 2'' PVC at this time.