Do Fence Posts Need Caps? (We Asked a Builder for Advice)

Do Fence Posts Need Caps

It’s time to build a new fence.  You know the basics you’ll need, including wood posts, a shovel, wire, etc.  But do fence posts need caps?  If so, what kind should you get, and why are they really necessary?  

Fence post caps are a necessary part of building a fence.  They help prevent mold and mildew from forming on your fence, and they help protect the wood from the elements, making your fence last longer. 

If you’re going to add a fence to your property, it’s wise to do the best possible job.  That’s why, in this article, we’ll be discussing all things fences and fence posts to help you ensure your fence is in top shape!

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Here’s a Quick Pro Tip!

There are as many post caps as there are fences.  You can choose from wood, metal, and plastic, typically.  Additionally, many caps have lights and other fun decorations on them these days. 

No matter what your aesthetic is, we think we can help you find the perfect fence post cap without breaking the bank.  Check out our three favorites:

1. Metal CapThese caps also double as aesthetic lanterns.

2. Wooden Cap –  These cedar wood fence caps will blend right into your fence!

3. Plastic CapThese PVC-based caps also provide extra light!

Fence Posts and Caps

If you’re going to build a fence, it’s worth it to do it properly.  But, if you don’t know much about fence caps, it’s easy to think they’re purely for aesthetics and forgo adding them to your fence. 

However, that’s not actually the case. So, let’s talk about why fence posts need caps.

Should I Put Caps on Fence Posts?

Fence caps should always be included on your fence posts because they help protect the posts from the elements and can prolong the life of your fence.  Additionally, they add a nice aesthetic to an otherwise plain fence. 

While you can add mold and mildew prevention to your fence posts, constant exposure to the elements may still hasten the demise of your fence posts.  Adding caps to them, however, can also help prolong their lifespan. 

How to Protect the Top of Fence Posts?

You can protect the top of your new fence posts by adding a fence post cap to them.  These caps help prevent water and sun exposure to the post itself, lengthening the life of your fence posts. 

If you truly do not wish to add fence post caps to your posts, you can choose to forgo them.  However, exposure to the sun, rain, and other moisture conditions will make wooden posts rot more quickly.

What Do Fence Post Caps Do?

Fence post caps are designed to cover the top of a fence post, preventing moisture from getting into the post itself.  Additionally, it shields the top of the post from sun exposure, which can hasten the wood to rot.

For metal fence posts, the caps also provide protection.  Without the cap, a metal fence post is more dangerous.  Leaving the tops exposed can cause damage to humans and animals should they fall onto them.  

What Are the Tops of Fence Posts Called?

Most fence posts have a cap on them.  These caps fit snugly over the fence post itself, whether wooden or metal, and prevent the post underneath from exposure to the elements.

Fence post caps ensure a long life for the fence post themselves.  Additionally, sharp or pointed fence post covers can help deter birds and other critters from trying to make a nest on a fence post.

What Size Fence Post Caps Do I Need?

To ensure you have the correct size fence post cap, measure the width of your fence post.  Then add 1/16 to ⅛ of an inch to that measurement, and that should be how large your cap needs to be. 

It’s important that your new fence post cap fits snuggly on the post.  If it is too loose, it may come loose and blow away in strong winds.  However, if it’s too tight, it won’t go over the post and may cause damage. 

How-to Install

As we’ve discussed why it’s important to add a fence post cap to your fence posts, let’s get to the important question, how to go about installing the caps.  Stick with us for full instructions!

How Do You Cap a Fence Post?

To properly cap your fence posts, you’ll need to ensure you have the correct size caps.  A fence post cap should measure 1/16 to ⅛ of an inch wider across than the post they’re going to cover. 

Then, just follow these steps to cap your fence post correctly:

  1. Measure your fence post width.
  2. Pick the correct cap for your fence post.
  3. Cover post in an adhesive.
  4. Carefully cover the post with the cap. It should be a snug fit.
  5. Allow the adhesive to dry completely.

How Do You Put Caps on a Fence Post?

Fence caps are designed to fit snugly over the end of a fence post.  For extra security, it’s recommended that you cover the top of the fence post with adhesive before adding the fence post cap.

You should be able to fit the fence post cap over the fence post carefully and just push it into place.  It should cover the fence post without damaging the post if you measure it correctly. 

How Do You Seal the Ends of a Fence Post?

Before adding a fence post cap, you should add mold and mildew-repellent spray and allow it to dry.  Then, add an adhesive and place the fence post cap onto the pole to ensure it is sealed properly. 

Adding an adhesive ensures that the fence post cap stays in place and helps seal the wood under the cap, guaranteeing that water will not seep through the cap and damage the pole underneath.

How Do I Make Post Caps Fit?

Start by measuring your fence posts.  Then add between 1/16 and 1/8th of an inch to the fence post measurement to determine the correct size for your fence post caps.  Those sized caps should fit properly.

Trying and manipulating your fence post is not recommended to get the caps to fit.  While it is theoretically possible to whittle down a wooden fence post to allow the cap to fit, you leave the wood more susceptible to water damage.

How Do I Attach a 4×4 Post Cap?

4×4 fence caps have two different common ways of attachment.  The first is the same as other fence post cap types.  All you need to do is add adhesive and press the cap onto the top of the pole. 

The second method uses screws to hold the fence cap in place.  Obviously, you’ll need a screwdriver to be able to properly adhere this type of fence post cap to your new fence. 


There are as many types of fence post caps as there are types of fences.  So, what do you need for your new fence?  Let’s talk about the types and how to tell which one will work best for your fence!

Do They Make Fence Post Caps Out of Wood?

There are plenty of wooden fence post caps.  Having a fence post cap made from the same wood as your fence can help it look like one whole unit instead of having an obvious cap on it. 

Wooden fence post caps can add a homestyle aesthetic to your fence.  Additionally, these fence posts are typically well sealed, so they should still protect your fence post without being overtly obvious. 

Why Do T-Posts Have White Tops?

When they think of fence post caps, many people think of the basic white plastic t-post caps.  While these caps do their job, preventing water from getting into the fence posts themselves, they’re not the only option.

Other common fence post caps include:

How Do You Attach Metal Post Caps?

Most metal fence post caps require drilling into the fence post itself to attach the metal cap onto the post.  For this type, you’ll need to use screws to place the cap onto the post permanently. 

Start by measuring your fence posts to determine if you have the correct metal cap size.  The caps should be between 1/16 and 1/8th of an inch larger than the pole. 

You should have no problem screwing them into the pole as long as they are correctly sized. 

Why Do They Put Metal Caps on Fence Posts?

Metal caps are often used on metal fence posts to protect the posts from corrosion due to extreme weather conditions. Additionally, they can provide a pleasing aesthetic for your yard.

If you have a wooden fence, you can still attach metal post caps to the posts.  They will help prevent wood rot and decay from forming inside the fence posts due to rain, sun, and snow. 

Other Troubleshooting

There’s so much to talk about when it comes to fences we figured we’d take some time to discuss other common issues and concerns people have while working on a fence.  So, let’s talk more about fence caps!

How High Should Deck Post Caps Be?

A deck fence, not including the post caps, should be at least 36 inches tall.  Then, the fence caps, or deck caps, should add another one to three inches in height.  This height ensures that the railings are safer. 

On that note, if you are building a deck or porch for your home, check your local laws and any applicable HOA rules before building.  Most states have guidelines for the height of your railings and more. 

What Is the Ideal Fence Post Cap Height?

The ideal fence post cap is about three inches in height.  This is enough to protect the top of a wooden or metal fence post from the elements without detracting from the fence itself. 

While some fence post caps are as small as one inch tall, having a slightly higher fence post cap is better for the post.  In fact, if you truly want to add height, you can add a whole lantern!

What to Do When Post Caps Don’t Fit?

If you bought custom fence posts and can’t return them or are unwilling to send your new post caps back for a replacement, you can attempt to sand down your fence posts to make the cap fit.

Just use caution if you choose to cut into the fence posts.  It’s recommended you only attempt to sand down the post, do not cut at it with a saw. 

Additionally, seal the post before adding the cap once you’ve completed the sanding.

Which Type of Fence Post Cap Is the Best?

Metal fence post caps are often considered the best type of caps. This is because they do not rot as wooden ones do.  They are also typically made from high-quality aluminum or corrosion and rust-resistant metal. 

However, the best fence caps are typically the ones that go with your fence.  For example, if you have a white picket fence, adding a white cap makes more sense than trying to shoehorn it on a metal one. 

You might also enjoy our post on Neighbors Hit My Fence

Related Questions

Does Capping Fence Posts Prevent Rot?

Capping your wooden fence with high-quality fence post caps is one of the best and easiest ways to prevent wood rot.  You can use metal, plastic, or even wooden caps.  

No matter what kind of cap you purchase, you should also consider sealing your wooden fence posts.  Adding a sealant is just another way to prevent water from being able to seep into your wood and cause rot. 

How Do You Fix Wooden Fence Post Caps?

If there is a small crack or break in your wooden fence post cap, you can attempt to seal the damage using wood glue or another high-quality sealant.  Unfortunately, you will need to replace the cap if that does not fix the leak.

The danger of trying to fix a broken fence post cap is that the cap can no longer do its job properly.  If it’s cracked, water may get to your fence post, which can cause mold and rot.  It’s typically best to replace the cap if this occurs. 

How Do You Remove a Fence Post Cap?

If the fence post cap is screwed into the fence post, you’ll first need to remove the screws.  Once they’re removed, you should be able to pull the cap off the fence post without hassle. 

If they’ve been glued on, you may need to use an adhesive remover before getting the cap off. 

Additionally, you may need to use a hammer to carefully tap all around the outside of the cap, which should loosen the cap enough for you to remove it.

Final Thoughts

Keeping your fence posts capped can significantly increase their lifespan.  Plus, it helps prevent birds from nesting and can cover sharp corners from metal fence posts.

So, all in all, it’s truly best for you to cap your fence posts!

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