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How to Prevent Fence Posts from Rotting?

Prevent fences from rotting with these tips

Because they are exposed to constant moisture, wooden fences tend to rot quite often. If your wooden fences aren’t stable and are weighed down by debris due to rotting, they could fall and you’d have to replace them every year or so. Several fence posts are required to be pressure-treated so that they can stand for a longer time, but there are more measures you can take to prevent the rotting from happening in the first place. 

For example, if you choose wood that is resistant to rotting naturally, including a variety of red cedar, your fence could last for decades altogether. Moreover, there is a treatment you can use, known as a wood preservative, which is also a great tool for prevention. 

Either way, here are some tips from our experts on how to prevent your wooden fences from rotting using liquid preservatives.


The location of your wooden fences during treatment is very important, as this will determine whether they will rot faster or not. Choose a dry and cool area that has a lot of air circulation so that the wood is kept as dry as possible. To prepare your fences and treat them with anti-rotting coatings, it is pivotal that they remain fully dry. In case your fences are dry already, specifically if you’re using greenwood fences, then go ahead with the treatment process. Greenwood tends to absorb moisture quickly and won’t be able to take in more preservatives if wet. In case you have decided to craft your fences from fresh wood, the drying process can be even longer, up to seven months or so.


The next step is to brush one-third or up to half of your fence post with a liquid wood preservative such as waterborne copper naphthenate. Make sure that the preservative doesn’t have chromium or arsenic. Brush this preservative across the whole post if you wish, but the bottom part is the most important as this section is buried within the ground and has a tendency to rot much quicker. To make the process even quicker you could place the fence in a standing position into a bucket that is filled with wood preservative, but this method isn’t the most functional in case you have to treat more than one wood post.

Waiting time

You must now wait for an hour or so, to ensure that the liquid preservative is absorbed into the wood. Then you need to put in a second coat for extra protection and wait for one more hour. Make sure that you don’t rush as it’s important to wait and let the wood absorb the liquid.

Additional coats

The more coats you can brush on, the better. You don’t have to stop at two. Keep brushing more coats until the wood stops absorbing it together. Once it stops, it’s a sign that the preservative has penetrated all aspects of the wood, into the sapwood and well into the heartwood too. Now, you need to keep them overnight before attempting to install them. 


To install these, you must first dig a hole that’s at least doubled or tripled the diameter of your fence post, between 24 to 48 inches deep. Posts are more stable when you bury up to one-third of the entire post’s length but if you aren’t able to dig that far, 24 inches should be ideal. Ensure that some part of the liquid preservative is exposed above the ground. 


Fill the hole you have dug up to quarters of the way of minus gravel, which has pieces of small gravel and also gravel dust that makes the setting far sturdier. Ensure that the gravel is packed tight and forms a sturdy base using a digging bar’s blunt end or a hand tamper.

Setting the post

Now comes setting the post which is an important step to prevent fences from rotting. Set your post inside the hole and make it level at the same time to make sure it’s straight. Now fill the hole around the fenced area with quarters of minus gravel to keep it packed tightly and efficiently. Tamp the gravel down, but do keep in mind to expose some liquid preservative above ground. In case you wish to use concrete you can, however because of its moisture content, it might lead to quicker rotting of wooden posts, and gravel is a better choice because it helps water drain faster from the fence and penetrate the soil.


The soil around the fence can be pushed above to make the gravel hidden. However, if you put moist soil around the fence, it could cause the fence to rot, and this is why we suggest treating a portion of the fence that’s still above the ground. The soil can be built up into a subtle slope surrounding the post so that there is more drainage and water doesn’t tend to collect at the post’s bade. 


Now it’s time to cut the top of your fence to the desired height. You can use a reciprocating saw and cut it at a slight angle so that water brushed off the top instead of collecting and absorbing into the wood.

Fence tops

Brush some of the liquid preservative into the top of the fence where the cuts that have been newly made are exposed and untreated. You can apply more coats after complete absorption.


In case there are any cracks around the wood or if they develop in odd places, you can use a small brush to coat these and make sure that it goes deep within the cracks. Wood tends to crack over time on its own, but if you don’t treat them, it can make a pathway to air and moisture inside, making the wood wet and causing it to rot.


Let the rails or fences dry on their own for some months before putting a coat of paint or wood sealer. If you do it too early, the paint or sealer can trap moisture inside the wood and promote rotting. In case you have let the posts air dry or are doing it in a climate where they can dry faster, such as Dubai, then painting faster shouldn’t be an issue.


After everything is dry, you can now paint the fence, pickets, and rails with exterior oil-based stain or latex paint to prevent your wooden fence from weathering and also increase the lifespan of posts that are above the ground.

We hope this guide helps!

Remember to always put safety first! Wear goggles, gloves, and breathing masks while working with liquid wood preservatives such as copper naphthenate preservatives, and try not to do this indoors, but rather, outdoors where there is more ventilation. We hope your wood stays in top form for the years to come.

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