What do you need to know about setting fence posts? The short answer is that setting fence posts properly keeps them from falling down as time passes, weather lashes, and mud oozes up from the spring rains. Moisture is the enemy of lumber and the friend of termites. Setting posts in concrete will help keep the base dry and impervious to pests.
You can do a lot of things around the home with fence posts. The most obvious purpose is that you can stretch prefab fencing sections between posts. You can separate your yard from your neighbors, establish a privacy screen, and keep your pets in the yard. You’ll also have to set fence posts if you’re building an arbor for your roses, or even an outdoor clothesline. If you live in the country trying to make a garden, it’s a good idea to fence it in with a post frame covered with some sort of steel mesh. That will save your vegetables and flowers from the deer. These are simple but common reasons you’ll have to set fence posts.
Setting fence posts is easier when you realize that home improvement and building supply stores offer ready-mixed bags of concrete expressly for that purpose. Read the bags in the concrete section of the store. The one you want will say something like ‘perfect for setting fence posts’. It’s an aggregate, a combination of gravel and cement.
In order to determine the number of bags you’ll need, you’ll first have to decide how many fence posts you’re going to set. Having done this chore several times myself, I tend to use half a bag of concrete per fence post, sometimes more. For super strength posts, I’ve cross webbed the hole with rebar and poured in a whole bag but that’s not necessary in most applications.
Four by fours are the most economical for setting posts. They’re strong enough and they come in convenient eight foot lengths. You can use thicker posts and longer posts (those used in upper level decks, for example, may be sixteen feet), but they are much more expensive.
Let’s suppose we’re using a 4 x 4 of an eight foot length. That means you’ve got to dig a hole two feet deep. You can rent a hole-digger if you’ve got lots of holes to dig or buy one of the manual ones to dig just a few. It’s important to go down at least two feet, leaving six feet sticking out of the ground. Six feet of above ground elevation is a standard set by many town building codes for fences in suburban areas.
Get a long mason’s level and level the post vertically in the hole. Support it in position with rocks and outside with bracing. Check the level continuously as bumps are likely to put it out of kilter. When you’re sure the post is perfectly plumb (vertically leveled), and stable, you can begin putting the dry concrete in the hole. Check the level again. You can wet and stir concrete in a wheelbarrow and pour it into the hole already wet, but you don’t have to. It’s much easier to put it in dry and begin to tamp it down until it’s hard. As you’re tamping, continue to check level.
If you’re having a problem with leveling, you can nail support sticks made of 2 x 2 or 2 x 4 for bracing. The bracing will be removed when the concrete hardens. Hardening of the concrete will begin when you pour water into the hole filled with dry concrete. Do it slowly so that its seeps in. Be sure the concrete is soaked. Make a last level check before the concrete begins to harden. Let the concrete cure for several days before removing the braces.
When you’ve removed the braces, the concrete should be all set and so will you. Where you’re setting one post for a bird feeder or one hundred for a long fence, the procedure is the same. Buy the materials. Dig the holes at least two feet deep. Stabilize and level the posts. Pour in the concrete and wait for it to cure.