Whenever a project calls for posts, like for fencing, a concrete post is a sturdy option that will last for decades. Unlike wood that can dry out, warp and decay over time, concrete does not break down. Concrete is also a green or environmentally friendly product. When using concrete posts, they must be secured and supported, just like wood posts. There are several ways to support a post made from concrete.
Wet Concrete Supports Concrete
One option is to use concrete to support a concrete post. Dig a hole deep enough to bury the fence post at the recommended depth, plus about 6 more inches. The hole needs to be about twice as wide as the post. Pour about 6 inches of gravel into the bottom of the hole. This helps keep the water away from the post, preventing it from rotting. Next, place the post in the middle of the hole. Use a level to plumb the post on two adjacent sides, not opposite sides. Brace the concrete post with a couple boards shimmied at an angle on the sides of the post and on the ground outside of the hole. Then, pour some dry cement into the hole, until it is about 1/3rd full. Add water and mix thoroughly.
Add another 1/3rd cement mixture into the hole and add water and then stir. Do this until the hole is filled to the top with concrete. The consistency should be like pea soup, if not, keep stirring and add water as needed. If it gets too runny, add more cement. Let the concrete cure overnight and then remove the braces.
Semi-Dry Concrete Supports Concrete
Another option for concrete posts support is to use semi-dry concrete. This is done in almost the same way as above, but instead of pouring cement into the hole and mixing with water, a semi-dry cement is poured into the hole and thoroughly rammed round the post. Post supports are not needed for semi-dry concrete and you can move quickly onto the next section of fence because there is no drying time. Also rammed concrete insures that there will be no movement in the post.
Spike It In
To lessen the burden of digging, use post spikes to support the concrete posts. A post spike is a metal spike that is about 24 to 30 inches long and has a 4x4-inch metal box attached at the top. This box is designed to hold the base of post. Drive the post spike into the ground and then put the bottom of the post into the metal box. Post spikes are typically inexpensive and make putting up a fence a lot quicker and easier as there is no need to pour concrete and dig holes.
Always start at a corner, putting a spike into the ground, the post into the box, and then use a sledgehammer to drive the post into the required depth in the ground. Straight spikes must go into the ground straight, but adjustable spikes can be a little off center without causing harm.