Setting fence posts in concrete ensures that they will remain rigid and perfectly upright. The posts are the foundation of any fence. If they have been set securely, your entire fencing project will be more durable, stronger and better able to stand up to nature. Many homeowners set their posts using Quikrete. But how much should you buy? Here are some ways to determine that.
Post Size and Hole Depth
The diameter of a post hole should be three times the size of the post you intend to set. As an example, for a round post with a diameter of 4 inches, the diameter of the hole should be 12 inches. When you dig the hole, make certain it is cylindrical with vertical sides and does not taper at the bottom. This ensures that the bottom of the post is set in the same volume of concrete as the top and helps prevent the post from leaning.
The depth of the hole is determined by how much of the post extends above the ground. The general rule is that one-third of the post should be buried in the hole. As an example, if the posts for your fence will be 6 feet high, you will use posts with an overall length of 9 feet and dig a post hole 3 feet deep.
How Much Quikrete
Quikrete has taken the guesswork out of determining how many bags you will need. On the company's website is a calculator on which you enter the depth of your post hole in inches and the calculator will tell you how many 50-pound bags will be required to set a 2-, 3- or 4-inch diameter post.
For example, a 3-inch post set 2 feet into the ground will require two 50-pound bags of Quikrete, and a 4-inch post set 3 feet into the ground will require five bags.
If you will be setting a larger post, you can call the company at 1-800-282-5828 and its engineering staff will help you determine how much Quikrete you need.
The online calculator does not provide figures for square posts such as 4-by-4s. However, a square 4-by-4 has a slightly larger volume than a 4-inch round post, so you will need slightly less Quikrete.