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How to stop fence posts rotting in concrete? If you don't know how to do it, we are here to help you. In this DIY guide, you will know the easiest way of stopping fence posts rotting in concrete. If you are confused about what to do now, you can follow our step-by-step guide. If you don't get into it, you can have a second opinion from our professionals. You can also contact our fencing professionals and choose one of them for solving the problem.

Fence posts are very sophisticated, but it is very tough to maintain them. It is very important to check once a month whether fence posts need any maintenance. Sometimes, exposure to moisture for a long time in the soil causes the rotting of wooden fence posts.

We will try to explain everything step by step to do it by ourselves without facing any issues while doing it. You don't have to be an expert if you follow our guidelines. However, before moving forward with the step-by-step guide, let's know all the equipment you will be needing while you try to stop fence posts rotting in concrete.

Checklist: Materials Needed to Stop Fence Posts Rotting in Concrete

  • Naphthenate Wood Preservative
  • Paintbrush – Wide and Small
  • Digging Bar
  • Gravel
  • Measuring Tape
  • Level
  • Reciprocating Saw
  • Hand Tamper
  • Latex Paint
  • Oil-based Wood Stain

How to Stop Fence Posts Rotting in Concrete [Step-by-Step Guide]

It might look that it is an easy task to stop fence posts from rotting. However, there are a few steps to follow while preventing fence posts from rotting in concrete. Let's look into the checklist and step-by-step process.

Step-01: Dry the Wood

Place the wooden fence posts in a cool, dry place with sufficient air circulation to allow the trees to dry. If your posts are already dry, you can skip this step, but drying is essential.

Moisture and damp wood promotes rot so If you use greenwood fence posts, make sure the wood does not absorb much. If you make your posts from fresh wood, it may take several months to dry.

Step-02: Cover the Wood with Preservatives

Cover the lower third or lower part of the fence post with water-based naphthenate copper, a wood preservative that does not contain arsenic and chromium. Sometimes, the entire pillar needs coating with preservatives.

However, the part embedded underground and the region just above the post should be treated much faster. Nevertheless, you can stand the pillars straight in a wooden preservative bucket which is not practical when dealing with multiple fence pillars.

Step-03: Let the Wood Absorb Preservative

Wait about 1 hour for the copper naphthenate preservative to be absorbed by the wood, then apply the second coating and wait 1 hour for it to soak into the wood.

Step-04: Coat the Wood with Preservative Again

Continue brushing the naphthene copper preservatives on the fence posts until the wood stops absorbing the preservatives, indicating that the preservatives have invaded the sapwood and heartwood. Allow the pillars to dry overnight before installing the fence.

Step-05: Dig Holes in the Fence

Dig a hole 2-3 times the diameter of the fence column and 24-48 inches deep. At least 24 inches is allowed, as the pillars are best erected but may not dig deep when they are one-third the length of the total posts. Some of the copper naphthenate wood gets exposed above the ground.

Step-06: Fill the Holes with Gravel

Fill the holes in about 6-inch 1/4 minus gravel. Here, crushed gravel includes for a better oath with a small piece of gravel. Tightly pack gravel on the blunt end of the hand tamper or discard bar to create a flat floor.

Step-07: Check the Vertical Alignment

To check the vertical, set the post in the holding hole to hold horizontal on the side. Fill the holes around the fence pillars with 1/4 minus gravel tightly packed on the sides of the pillars. I stepped on the gravel. Concrete can be helpful if desired, but the moisture in the concrete causes the wooden posts to rot faster, while the gravel allows the water to drain quickly into the soil at the fence pillars.

Step-08: Tighten the Foundation of the Fence Post

Push the soil around the fence pillars to hide the gravel. Moist soil around the fence pillars can rot the posts, so some of the wood exposed from the floor needs treatment. The soil was piled up on slopes around the pillars to promote drainage and prevent water from accumulating on the posts and floors.

Step-09: Check the Desired Height

Cut the top of the fence pillar to the desired height with a reciprocating saw, cut it at a slight angle, and instead of the water collecting and being absorbed by the tree, it will flow down from above.

Step-10: Applying Wood Preservatives

A water-based copper naphthenate wood preservative is brushed onto the pillars of the fence to expose the newly cut parts and expose the untreated wood. Apply additional coating after the first coating absorbs by the wood.

Step-11: Handling Cracks

Apply copper naphthenate wood preservative for cracks that occur from anywhere in the fence pillars. Use a smaller brush to allow the preservative to penetrate deeper into the cracks. Wood cracks naturally over time, but if the gaps are left untreated, the inside of the prop is getting air and moisture exposure, and the wood can quickly rot.

Step-12: Preventing Wood from Rotting

Wind all fence posts and rails for several months before applying paint or wood finish to the wood. Therefore, the paint and finishing materials trap moisture inside the wood and prevent it from rotting upside down. You can paint the posts immediately if you let the period sufficiently wind before applying the preservative, but you need to make sure the wooden rails are completely dry.

Step-13: Applying Dry Fence Columns

Apply dry fence columns, rails, and placards to external latex paint or external oil stain to protect the wood from weathering and extend the life of the columns on the ground.

Choosing Lumber Wisely

We need to Choose which timber is being pressure-treated. This tree looks "green" and is sometimes called Wolmanized, which means they need treatment with preservative chromium copper arsenide.

Alternative options for pressure-treated wood include Western Red Cedar (A long-lived, natural non-rotting timber), White Cedar or Black Locust (Prevents mould growth suitable for wetland environments), or Cypress or redwood (natural water resistance).

Why Use Treated Wood Poles?

Untreated Ground Pine Poles can only last up to 6 months. The use of treated posts guarantees longevity. There is a consensus that some fence builders wrap the base of the prop with copper or galvanized steel to extend the life of the tree further, but it works well with treated posts.

Set in Gravel

When the pillars are processed, it is the order of installation on the ground. You will want to dig a hole about twice the diameter of the fence pillar and only the frost line. This depth can be from 16 inches to 42 inches.

Check local building regulations for this depth. Fill the first 3 inches with gravel to keep the tip of the post from contacting dirt. Gravel allows water to drain quickly from the poles into the soil.

Be Sure to Place the Post in the Center of the Hole

Finally, fill the entire hole with cement to the top. Secure the concrete fence and prevent lateral movement. The concrete top is dome-shaped and away from the pillars to drain water from the posts for more protection.


When working with copper naphthenate preservatives, it is essential to wear gloves, goggles, and masks and work in a well-ventilated area, preferably outside. Over hours, the pillars of the wooden fence may begin to rot and worsen after prolonged exposure to the moisture of the surrounding soil. If these columns lose their structural integrity, the fence easily breaks, and the columns need replacement.


Did you get the answer to "How to Stop Fence Posts Rotting in Concrete?" Always remember, when creating fence columns from freshly cut wood, it is essential to use copper naphthenate wood preservatives, which should be freely applied to the entire fence columns.

Frequently Asked Questions :

Will Fence Posts Rot in Concrete?

There is a chance that the fence post will rot in concrete. As the pressure-treated posts are in use, the fence post will rot slowly.

What Causes Fence Posts to Rot?

There are many causes for fence posts to pot. However, one of the causes can be a decomposing sap in the posts.

Will Pressure Treated Wood Rot If Buried?

Observing situations, pressure-treated wood rot slowly. On the other hand, pressure-treated wood will rot fast if buried.

How Long Will a Pressure Treated Fence Post Last?

As we know, pressure-treated fence posts rot slowly. In most cases, pressure-treated posts may last from twenty to thirty years.

Why Deck Posts Should Not Be Set in Concrete?

Researches show deck posts can be fragile. So, deck posts should not be set in concrete because they can break.

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