Do You Put Concrete Inside Vinyl Fence Posts?

Vinyl fences are growing in popularity as an alternative to conventional wood pickets or rails. Want to know if you can pour concrete inside the vinyl posts?  In order to assist you with this situation, we did some research on this subject. 

You can fill concrete inside the vinyl fence posts. Vinyl fencing is constructed to last from the ground up, and that construction begins with a strong concrete base that maintains the posts steady and true for a very long time. 

This article will go into great detail about pouring concrete into vinyl posts. We'll go over how to install it step-by-step, the ideal concrete grade for these vinyl posts, and more. So keep reading.

Do You Put Concrete Inside Vinyl Fence Posts?

Posts at the gate end and corners must support or bear additional loads and thus should be filled with concrete for stability. Your soil goes through a lot of expansion and contraction due to the seasons and the elements, and the concrete will help protect against any unwanted shifting as well.

Vinyl fence on the lawn

The installation of vinyl fence posts into concrete can help to ensure that they are held in place extremely firmly because concrete is a highly strong material.

Since the concrete will prevent the posts from being yanked out of the ground, this is particularly crucial if you live in an area with strong winds.

Concrete's primary drawback is that it is laborious. If you're not careful, your fence can end up being incredibly uneven. Without a stable footing or foundation, when a fence is built, it will surely shift up and down, in and out of the soil.

Therefore, there is no practical way to drive vinyl posts into the ground without damaging the post since they are too big to do so. The best technique to secure the works is using concrete after a hole has been dug.

How Do You Install Vinyl Fence Posts Using Concrete?

Concrete can be poured into vinyl fence posts, but if the proper procedure is not followed, it won't work. If you've ever attempted to fill one of these posts with concrete by simply pouring it and tamping it down, the cement simply seems to want to suck back out of the posts.

This procedure is more than merely pouring dry concrete mix into the post. You must get the post ready for filling. 

The vinyl fence post is a typical sight in suburban America. Despite not being as strong as a wooden one, it has some benefits over wood. 

For instance, you don't have to worry about maintaining it and you can paint them any color you want without thinking about if it will match your house. There are a few steps you must follow in order to successfully fill a vinyl post with concrete,

1. Plan And Mark the Post Locations

Spend time carefully planning the fence's post location. Mispositioning posts might lead to issues later. Plan ahead for the lengths of the fence panels and gates to avoid having bays that are an odd size and complicating installation.

Stake out the whole length of your fence line, including any gates and corners, using landscape stakes. Place a string tautly tied between the corner posts. This string will help to specify where the posts will be positioned.

Click here to see these landscape stakes on Amazon.

Then, decide the places for your fence posts. Use a stake to identify each post's placement. To keep the posts straight, make sure the stakes are contacting the layout string. 

2. Dig Post Holes

Digging up dirt for post

Dig holes 10” in diameter (sometimes the instructions that come with the fence will specify the necessary diameter) on the marked spots for the posts with a power auger or post hole digger. The depth will vary depending on the local soil characteristics. 

Click here to see this post-hole digger on Amazon.

In order to allow for gravel backfill before the hole is filled with concrete, dig the holes 6” deeper than necessary. A good rule of thumb is to bury ⅓ of the post.

3. Backfill The Hole With Gravel

To direct water away from the post's bottom, backfill each hole with 6” of gravel. Use a wheelbarrow and a shovel in this operation to help it go more quickly.

Click here to see this wheelbarrow on Amazon.

Click here to see this shovel on Amazon.

4. Pour Concrete On The Holes

Concrete pumping hose filling foundation hole

Mix the concrete at a ratio of one part cement to two parts sand. Then add water to the mixture until it has the consistency of pancake batter. Alternately, use quick-setting concrete to expedite the procedure, but be sure to follow the directions for how long the concrete needs to cure. 

Click here to see this cement on Amazon.

Pour concrete into the hole once the gravel has been added. To completely cover the posts, make sure to fill the holes all the way to the top. After placing the concrete, you must tamp it down to make it level with the ground. To do this, use a piece of wood or a tamper.

Click here to see this tamper on Amazon.

5. Tap The Posts In Place

To fill the post's middle portion in the hole, tap the hollow post into the concrete. Tap it until it reaches the top of the gravel. Level and plump each post.

Click here to see this level on Amazon.

Fill in the top-hole gaps excessively. To prevent water from accumulating around the post, slant the concrete away from it with a trowel.

6. Allow The Concrete To Dry 

Post with cement at base in front of fence

Wait at least 24 hours for the concrete to set before adding any fencing. This will give the concrete enough time to dry and solidify before the weight of the fence is applied.

You can check on things from time to time by giving them a rap with your knuckles as you wait for them to dry. Don’t forget to keep checking on the alignment and plumb one more before the concrete sets, and make any necessary adjustments.

7. Attach The Vinyl Fence Panels And Other Accessories

When the concrete is set, fasten the rail brackets to the fence posts using the required screws of the manufacturer. The brackets and screws will differ depending on the kind of fence that is being installed. Then, slide the panels into the brackets and use screws to secure them.

In order to have an even fence, you must ensure that they are level with the top of the post. This will guarantee the fence's safety and ability to endure strong winds. To give the post a finished appearance, you may optionally add a cap to the top.

To visualize how the process is done, a video on YouTube is shown below.

What Is The Best Concrete Grade To Use For Vinyl Fence Posts?

What Is The Best Concrete Grade To Use For Vinyl Fence Posts

You'll need to decide between “high-strength” or “fast-setting” concrete premix when installing vinyl fence posts. Both are reasonably priced and feature a cement, sand, and aggregate mixture that is ideal for your vinyl fence.

More information about these concretes is listed below to assist you in planning and preparing for the installation of your fence.

High-Strength Concrete Mix

  • They are strong and extremely versatile as they are not just ideal for vinyl fence posts but also used for footings, foundations, walkways, and patios.
  • Gives you plenty of time to move and position posts, even the most obstinate vinyl fence posts.  If your mixture begins to become too dry to handle, simply add water to the mixture.
  • The high-strength bag of concrete is often one of the least expensive bags of concrete offered at the store. The price per bag is often $1 to $2 less than that of a fast-setting mix. 
  • You can purchase this in multiple weighted bags (40lb, 50lb, 60lb, or 80lb). Depends on your needs.

Fast Setting Concrete Premix

  • Within 30 minutes, this premix concrete will solidify to a point where it is impossible to remove it from the post. The premix that sets the fastest do so in five minutes though it typically costs more.
  • Water is needed, but there is no mixing required. Simply place your post in the hole, fill one-third of the hole with water, and then pour a bag of this concrete. Without stirring, the water will permeate the entire mixture, and the premix will set in just a few minutes.
  • It is also high strength, which makes it very adaptable which makes it suitable for patios, sidewalks, and footings too.

Do Vinyl Fence Posts Need Wood Inserts?

Lush cornfield with white fence and blue sky

Wood inserts on your new posts increase their stability and the stability of the entire fence system. However, placing a wooden post within your vinyl post and pouring the concrete can be problematic if there is improper drainage. In that scenario, it actually accelerates the decaying of the post by acting like a sponge.

But there is still hope if you are fixing an old post with a rotted wood insert! You can offer additional stability and support with a fence post mender or spike.

You could insert a wood post if your post is entirely hollow, but it is not advisable. Although these vinyl posts will fit over the wood posts, they won't fit tightly.

To achieve a snug fit, you will need to shim the difference. Even so, other manufacturers made their posts fit snugly, but doing so could cause the shell to shatter.


A great approach to save money is to fill vinyl fence posts with concrete. In addition, it's simple if you have the necessary supplies on hand and can adhere to directions. Concrete filling for fence posts can be enjoyable and gratifying if your cement mixture is just perfect.

Before leaving, check out some interesting articles we have below.

How Much Space Between Fence Posts?

Should You Set Deck Posts In Concrete?

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