This is the last of a 2-part amateur demonstration of how I replaced a post that was rotted out from underground moisture. After removing the old post I modified the concrete pier so that the wood will be entirely above grade. This video is a good demonstration of what happens when wood supporting posts are sunk below ground level. Before doing any home renovations, be sure you have read and understood your risk and responsibility. Specifically you need to understand whether your local building code requires a building permit, and you should inquire from local building inspection services whether additional work is required. Any misadventure you encounter if you decide to repair your home is your responsibility.