Do Vinyl Fence Posts Need Wood Inserts?


Vinyl fences are a great option when considering installing a fence. There are a few things to consider, though. 

Typically, vinyl fence posts do need some sort of reinforcement, like wood inserts, to ensure longevity and integrity. Wood inserts are a good short-term option to help secure vinyl fence posts. 

Given this answer, you might think that inserts are simple or easy to install, but there is actually a lot more that you need to know so you can properly reinforce your vinyl fence.

Are Reinforcing Inserts Needed?

Vinyl fences are a great long-term option when choosing a fence material. They’re easy to keep clean, usually pretty simple to repair and replace, and stand well against the elements.

Usually, vinyl fences require any sort of reinforcing insert in the posts. One thing to remember is, even though vinyl typically bodes well with bad weather, wind can sometimes be an issue.

Because vinyl fence boards don’t have much space between them, wind can’t pass through very easily so a vinyl fence tends to wobble a bit in high winds. If this happens frequently, the fence could eventually fail; which is never ideal.

Vinyl posts are hollow and are made specifically to cover some sort of reinforcing insert. So, in high wind areas, some sort of insert is needed, but not necessarily wood ones.

Frequent high winds shouldn’t be an issue, as long as the vinyl fence is installed correctly, with reinforcing inserts in each of the posts.

How to Install Inserts

Whatever material you choose for the insert, the installation process is basically the same.

Once the measurements for the posts have been made and the holes have been dug, the insert is placed into the hole. Then, slide the vinyl fence post over top of the reinforcement insert.

No matter what insert material is used, the post needs to be set in concrete. So, after the vinyl post is placed over top of the insert, pour concrete around the base and let it set.

Now that the posts are set in the concrete, the vinyl boards can be installed.

Is Wood a Good Reinforcement Option?

There are differing opinions about whether or not wood is a good material to use for inserts under vinyl posts. Wood has a lot of great qualities and it’s very sturdy when it’s installed correctly.

That being said, there are a lot of things that could go awry if wood is used as the reinforcing insert.

Pros:

Like mentioned above, wood is very solid and sturdy. Once it’s set in concrete, under the vinyl post sleeve, it tends not to waver or collapse.

It’s also one of the cheapest and easiest options for inserts. Most large chain constructions companies recommend wood and even have pre-cut inserts available for purchase.

Cons:

Because wood is a natural material, it is subject to the elements a bit, specifically water. Although it tends to stand well against occasional rain and snow, constant water and moisture could cause issues.

Wood tends to retain water really well, especially if it doesn’t have access to air or the sun which, if it’s being used as a reinforcing insert, is precisely the issue.

If the wood inserts are not properly treated before they’re installed (so if it’s raw, fresh wood) it’s subject to breakdown, dry rot, and eventual failure.

That being said, the wood inserts would still last for at least 5 years, but will definitely need to be replaced by then to avoid having to replace the fence as a whole.

All hope for wood inserts is not lost, though! It’s still a good insert material to use as long as it’s pressure treated before it’s installed. Pressure treated wood can be bought pretty much anywhere wood is sold.

Other Reinforcement Options

If you want to avoid any issue with using wood for the reinforcing inserts of a vinyl fence, there are a couple more options and materials for the inserts:

  • Concrete
  • Rebar
  • Steel

Concrete

This is the most common reinforcing insert that is used in vinyl fence posts, other than wood.

This is also a pretty simple one to use since the posts need to be set in concrete, anyway. The process is a bit different, however.

Once the holes are dug for the posts, pour the base concrete into the hole. Then place at least 2 rebar posts in the concrete base. Before the concrete sets, place the hollow vinyl post over the rebar posts and let them set.

After the poles are set in the concrete and the base vinyl rail is placed, pour more concrete into the top of the hollow vinyl post and let is set up.

The rebar posts will help bind the concrete together and maintain its stability and strength.

Rebar

Another option for inserts is just plain rebar posts, without the added concrete.

The installation process for rebar inserts is basically the same as the concrete posts, with a few caveats.

Instead of just 2 rebar posts, you’ll need to place 4; one in each corner of the concrete base, just smaller than the diameter of the vinyl fence post so it can slide over them.

Then, you just omit the last step of pouring extra concrete once the vinyl post is set.

Steel

Steel reinforcing inserts can be used for vinyl fences, as well. These are definitely the strongest and most reliable option, but they are also the most difficult.

These aren’t readily made for this purpose, so they would end to be specially fabricated for this project. This could also be pretty expensive since you’ll need one under each vinyl post.

It also might be difficult to install the vinyl fence posts over the steel ones; because steel and vinyl both are flat surfaces, while you’re sliding the vinyl over the steel, there may be a lot of surface tension and it could be very difficult to slide.

So, the steel insert would need to be slightly smaller than the vinyl post in order to install it properly. Then, the vinyl post might wobble a bit since there’s space between the insert and the post, but it shouldn’t be too much.

Again, a reinforcing insert is only necessary if you live in an area with frequent high winds. Otherwise, you could go without installing any insert, at all.

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