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How Deep Do I Dig Fence Post Holes? Tools, Factors, & FAQ

wood fence

Digging post holes is crucial for having a sturdy foundation. Whether you choose to have a wooden, vinyl, or metal fence, digging holes for posts will be the first step to ensuring a solid structure. When asking how deep should a fence post be, the general rule is that they need to be one-third of the above-ground height of the fence.

Although many different factors come into consideration when digging posts holes, this article will cover the information you need for their ideal depth.

divider 7 The Importance of Post Holes

person digging trench
Photo Credit By: Will478, Shutterstock

When building your fence, it needs to have a solid and sturdy base, especially if the fence is wooden. Post holes act as roots, holding up the rest of the fence and keeping the fence mounted to the ground. They are crucial in creating a long-lasting and secure fence that will stay intact. When constructing your fence, it is essential to consider the factors it will have to withstand—it will constantly be exposed to inconvenient weather, so it must be strong and secured properly underground.

Before You Start

Before digging post holes, it’s crucial to gather all the tools and materials necessary for this project. You will want to dig holes properly on the first try, so it would be best to make a couple of sketches and plans before digging. You’ll need to plan the fence’s location perfectly because there is no going back once you start with all the work. Think about the distance between the posts, and consider that the holes will need to be much wider than the actual post. Make sure not to collide with other underground water pipes or gas pipes.

Tools You Will Need:

How Deep Should A Fence Post Be

The primary rule of digging post holes is the deeper the hole; the more stable your fence will be. The ideal ratio would be a hole that is one-third or one-half of the above-ground height of the post. For example, if you have a post that is 6 feet tall, the post hole would need to be at least 2 feet deep. The minimum depth for all post holes should be 2 feet.

The holes are then filled with concrete to stay solid for a long time. There are other methods for filling holes, such as filling them with soil and gravel and firmly tamping each layer. This method is excellent for changing poles in the future if they break or rot.

bamboo fence
Photo Credit By: FreeImagesGuide, Pixabay

How Wide to Dig Post Holes

The general rule is that the hole should be three times wider than the post width. For example, if your post is 4×4 inches wide, you should dig a hole at least 12 inches wide.

How Deep to Dig Post Holes for Gates

Post Holes for gates have to be at least 32 inches deep. It is necessary to dig holes that are this deep because the posts will have to withstand the weight of the gate. Because of the constant movement of the gate, poles are very easy to loosen or move out of place, which is why it is best to set these holes with concrete.

Post height 4 feet high

3×3 inches wide

6 feet high

4×4 inches wide

6 feet high

5×5 inches wide

6 feet high

6×6 inches wide

8 feet high

8×8 inches wide

Post hole depth 1,5 foot deep 2 feet deep 2 feet deep 2 feet deep 3 feet deep
Post hole width 12 inches wide 12 inches wide 15 inches wide 18 inches wide 24 inches high

How Many Bags of Concrete do You Need for Filling Post Holes?

Depending on the size of your hole and the size of your yard, you may need to buy a large amount of bagged concrete. Typically, for a post hole that is 10 inches wide and 2 feet deep, you will need approximately three and a half, 40-pound bags of concrete for just one hole. Consider filling the holes with concrete and shaping the concrete into a dome to guide the water away from the post.

Picket Fences
Image Credit: PublicDomainArchive, Pixabay

How Do I Put a Post in the Ground Without Concrete?

When digging post holes that you will fill with gravel instead of concrete, start by digging them 4 inches deeper than usual. If the hole for your post should be 2 feet deep, then dig 28 inches in depth to leave room for gravel. When it comes to the width, instead of digging the usual three times wider than the post’s width, dig twice the diameter of the post. First, pour 4 inches of gravel and then set the pole in place on top. After setting the post in place, start adding and tamping the gravel layer by layer.

divider 7 Final Thoughts

As we mentioned, it is essential to plan everything before sinking your fence posts. Sketch the spaces for your fence, and calculate the sizes of the holes necessary. You will also need to think of their exact locations ahead of time. Digging fence post holes can be challenging, but you will save a lot of time and energy if you set up everything in advance.

See Also: How Much Concrete per Fence Post Is Best to Use – What To Know

Featured Image Credit: romakoma, Shutterstock


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