If you are not familiar with installing wood posts, you can become overwhelmed with the various designs for concrete footings out there. This is the concrete footing we use for various projects. It is designed to protect wood posts by allowing the bottom of the post to be exposed for drainage to help reduce the chance of the wood rotting.
Dealing with reducing the potential damage from water is the biggest challenge in outdoor construction projects. Wood posts are exposed to moisture above ground and below. If you want to learn more about protecting wood posts above ground, you can read about that here.
How to Build a Concrete Footing
The sketch below shows how to make a concrete footing for a wood post. The bottom 6? of the hole is filled with 3/4? coarse aggregate. The post is set on top of the?aggregate and the concrete is placed around the sides of the post. Note also that the top of the footing, at grade, should be sloped away from the post for drainage.
Above ground, if the post gets wet or has condensation on it, the water can find it?s way? in between the concrete footing and the post, and travel downward through this seam. Not encasing the post end in concrete allows any water to be released into the voids created by the aggregate, which helps to keep the post dry. If the water was trapped inside a footing, the post would be wet indefinitely.
The depth of your post footing will depend on your local frost line. Check with your local building department to comply with code. Also, it?s good practice to Call 811 before you dig.