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How to Dig Post Holes and Set Fence Posts

October 1, 2020

By Ashley VanderWall

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Fence posts are the backbone of your fence, so it’s crucial they are set properly. In this blog, we’ll walk you through how to dig a post hole and properly set fence posts in concrete.

Getting Started

1 - Preparation.

Before you start the project, make sure you call your local utility companies to have them mark underground cables and pipes. It’s also a good idea to discuss your project with any neighbors along your fence run if you haven’t yet.

2 - Gather your tools and materials.

To dig a post hole and set a post in concrete, you’ll need some tools:

  • Post hole digger or power auger
  • Cordless drill
  • Screws
  • Hammer
  • Level
  • Tape Measure
  • Shovel
  • Bucket
  • Pieces of 2x4 scrap
  • Stakes and string

You’ll also need the following materials:

  • Quick-set concrete
  • Gravel
  • Access to water

The amount of concrete you need will depend on the size and depth of your post hole. Determine how deep you need to dig your post hole. Then, check the chart on the side of the concrete bag or use an online calculator to determine how much concrete and water you’ll need.

How to Dig Post Holes

3 - Mark your fence run.

The first step to any fence project is marking the exact location of your fence run. To do this, drive stakes into the ground at the corners and ends of your fence run. Stretch heavy string between the stakes and pull tight. This string line will help you set your fence posts in a straight line.

Mark fence run with string line

You can check that your corner is square by using the 3-4-5 rule. Measure three feet down one side of your corner and mark the string line. Then, measure 4 feet down the other side and mark. The distance between those two marks should be exactly 5 feet. If it’s not, adjust your stakes until you achieve that distance.

4 - Mark your post hole locations.

Next, you’ll want to mark your post hole locations along the string line. Post hole spacing is dependent on the width of your fence panels and the method by which you are attaching them to the posts. Typical post spacing is 8 feet, but can vary depending on the width of the fence panel.

There are two main methods for attaching the fence panels to the posts – Face Mount or Between the Posts.

Face Mount

Face mounting is the more common way to attach panels to posts, as it’s a little more forgiving. If you’re attaching fence panels this way, you’ll want to measure your post spacing on-center. You’ll also have to decide whether you want your fence panels to meet at the corner, or if you want one side to overlap. If you want them to meet, subtract 1-3/4 inches from both sides. If you want them to overlap, you can subtract an additional 1-1/2 from one side

Face Mount Privacy Fence

Between the Posts

Mounting your panels between the posts requires more precise post hole spacing but offers a neighbor-friendly look. If you’re using this method, you’ll measure your post spacing inside-post to inside-post. You’ll also want to dig your post holes and set posts “along the way” – as opposed to all up front – to maintain precise spacing through the full fence run.

Horizontal Panel Mounted Between Posts

5 - Start digging.

Now that we’ve marked our post locations, it’s time to start digging. In general, the post hole should be one third as deep as the fence is tall. So, if you’re installing a 6-foot tall fence, your post hole should be at least two feet deep. You’ll also want to be sure the bottom of the post sits below the frost line. For more information on post hole depth, check out our blog on the topic.

You can use a post hole digger or power auger to dig the hole. A post hole digger is a manual tool and will get the job done in average soil. If you have hard, rocky soil or a lot of roots – you may want to opt for a power auger. Many home improvement stores have them available for rent.

How to Set Fence Posts in Concrete

6 - Pour in gravel.

After you have your post hole dug to the proper depth, pour in a few inches of gravel in the bottom of the hole. This will help with drainage.

7 - Place and brace your post.

Set your post in the hole. Check for plumb and make sure the front of the post is just touching the string line. This will help you set your fence posts in a straight line. Having a friend help you will make this much easier.

Set post in hole on gravel

Now that the post is in place, brace it with 2x4’s so it won’t move while the concrete cures. Drive stakes into the ground, then fasten your scrap pieces of 2x4 to adjacent sides of the post.

Drive in stakes with hammer
Fasten 2x4s to the post

Double-check for plumb and adjust as necessary. Then fasten the other end of the 2x4s to the stakes.

Fasten 2x4s to the stakes

8 - Pour in concrete.

Pour the quick-setting concrete mix directly into the hole and pour water on top.

Pour concrete
Pour water

Mix it up with a shovel in the hole, which will simultaneously remove air pockets. Once the concrete is thoroughly mixed, push some soil back on top of it. Re-check that your post is plum. Adjust the brace if needed.

Mix concrete in hole

9 - Let it cure.

Follow the instructions on the bag as to how long the concrete should cure. In the meantime, you can install your next post. Follow the same steps, keep a close eye on spacing, and reference your string line all the way down the fence run.

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