How Much Concrete Do I Need for a 4×4 Fence Post

By Mike

February 24, 2021

A wood fence adds privacy to your home and defines your outdoor space well. Wood fences are common because they are incredibly durable and can last for years when installed correctly. More and more people are deciding to install their wood fences themselves. While this is absolutely doable, you need to know the proper steps to take to install it correctly. One major question people ask is how much concrete they need to use for a 4×4 fence post.

For 4×4 fence posts, you need 1 ½ bags of concrete per hole. Many people recommend premixing your concrete for a stronger hold. When you use an adequate amount of concrete, and you place your posts at least ⅓-½ of the total height in the ground, you will have a strong and durable wood fence. 

In this article, we dive into why you need so much concrete for one fence post, as well as how deep to place your fence posts, and more. 

How Much Concrete Do I Need for a 4×4 Fence Post

You may be thinking, one and a half bags of concrete per hole is an absurd amount for one post. When setting fence posts, you will dig down around ½ of your desired fence height. That means if you want a six-foot fence, you will dig a three-foot hole. That is a large hole, so the amount of concrete needed to fill it adequately will be a good amount. 

If you are embarking on building a wooden fence in your backyard, it is important to set a solid foundation with solid concrete for your posts to set in. Knowing how much concrete to buy is often hard to figure out for most people, and the last thing you want to have happened is halfway through a job and out of concrete. 

There are also a variety of calculators all over the internet that will allow you to type in the height of your fence and the area you need to build around. It will give you a number of just how many bags of concrete you need for your entire fence, starting you off right. 

Should I Use Concrete for Fence Posts

Concrete is incredibly strong and a great opinion to create a strong and durable fence. There are a variety of types of concrete that you can choose from. When using concrete for fence posts, it is crucial to remember to think about the outside temperature. Typically, temperatures between 50 to 90 degrees is the optimal temperature that will allow your concrete to cure properly. 

Concrete is truly the best material to set your fence posts in because it ensures your fence will not move around, and it will stay in place. 

Fast Setting Concrete

Fast Setting Concrete is a great option when needing concrete for fence posts because of how quickly it sets up. Fast Setting Concrete does not need to be premixed with water, minimizing the effort and mess you have to clean up after. 


Concrete

Many professionals swear by the fact that premixing your concrete is the best way to ensure a solid foundation for your posts. By premixing the concrete, you can mix it beforehand in a container and then move from hole to hole filling them up as needed. 

How Long Should I Let Concrete Cure Around Fence Posts 

When you use Fast Setting Concrete you simply pour dry concrete into the hole and fill it with water. Within 30-60 minutes, your concrete will be set, and after 4 hours you will be able to continue to work on your project. 

Within 24-48 hours of using regular concrete, it will be cured enough to continue on with your fence construction. Giving your concrete adequate time to dry will help you continue on building your fence with solid posts to support the weight. 

Is Two Feet Deep Enough for Fence Posts 

When it comes to burying your fence posts, there are some crucial steps to take to ensure your posts are secure, and your fence will last for years to come. Deciding how too deep to bury your fence posts is the difference between a fence that topples over in a wind storm and one that stands strong no matter what comes its way. 

Ideally, you can calculate this depending on how tall your fence is going to be. Calculating the depth at which you bury your fence posts comes down to burying ⅓ to ½ of your fence height. For example, if you are planning for a six-foot fence, around three feet should be buried below the surface.

By burying ⅓ to ½ of the total height, you provide your fence with immense stability and a strong foundation to continue to be built on. 

How Long Will a Treated Fence Post Last in The Ground

Treated fence posts versus untreated fence posts is an absolute gamechanger for your fence and knowing the difference is essential. When you place your treated or untreated wood in concrete, it will eventually rot because there is no way for moisture to escape from the concrete. 

The difference between treated and untreated fence posts is how long it takes to begin rotting. With treated fence posts, when installed correctly, they can last upwards of 20-40 years before they need to be replaced. Compare that to untreated fence posts that will likely need to be replaced in only a few years. 

Installing a new fence takes a lot of time and effort, so choosing the correct wood will keep you from having to repeat the process in a few short years. You will also need to consider the type of wood you want to build your fence out of. 

Cedar fences last the longest, with life spans around 40 years versus spruce, 4-7 years, and pine, 7-12 years. Selecting treated wood and cedar fences will allow you to have a strong fence for years and years.

Conclusion

Building your own fence in your backyard to provide privacy and add beautiful curb appeal can be accomplished by taking certain steps to ensure its longevity and durability. When it comes to building a fence, many people wonder just how much concrete they will need for a 4×4 post. 

For a 4×4 post, you will need around 1 ½ bags of concrete to use in each hole you dig. When you hear that number, it surely sounds like a large amount of concrete, but you must remember just how large of a hole you will be filling. 

When you dig your fence post holes, you will be creating a hole that is ½ the total height of the fence you are wanting. For a 6 foot fence, you will dig a three-foot hole and will need to fill that hole with a fence post and concrete. 

Another aspect to be aware of is the type of wood you are using for your fence post, what type of concrete to use, as well as always using treated wood to make your fence last longer. A fence is a great choice to define areas of your yard or simply add a layer of privacy to your space, and you can DIY one yourself by following the guidance above. 

About the author

Hi I'm Mike! I'm the owner, writer, and sometimes editor of Foundedproject.com. Being a new homeowner can be a little daunting, which is why I created this blog. I write about problems that a new home owner might run into. 

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