Can You Pour Concrete Around Treated Posts?

Let’s Talk About Concrete, Posts, and Getting It Right

Working with concrete and posts is a common DIY task, especially when it comes to building decks, fences, or raised garden beds. But you might be wondering: can you just pour concrete directly around treated wood post? The answer isn’t as straightforward as it seems.

Firstly, let’s address the elephant in the room – treated lumber is designed to resist rot and insects. It’s a good choice when dealing with outdoor projects. However, this same durability can sometimes lead to confusion about how to best handle concrete around it.

You see, treated wood posts are inherently strong and stable. The chemicals used during the treatment process ensure they resist moisture and decay for a long time, making them ideal for outdoor construction. But these very properties make them slightly different from standard wood in terms of interaction with concrete.

For instance, the chemicals in treated lumber can react with the water-based concrete mix. This reaction can lead to unwanted changes in the wood’s structure and even weaken its resistance against harsh weather conditions. It’s not a disaster, but it does require careful attention during project execution.

Here are some further reasons why pouring concrete directly around treated posts might not be ideal for every scenario:

• Concrete Expansion:

Concrete expands and contracts as it cures. This expansion can sometimes put pressure on the treated wood, potentially leading to uneven settling or even warping of the post.

• Chemical Interaction:

The chemicals in the concrete mix react with the chemicals used during the treatment process of the posts. This reaction can affect the longevity and structural integrity of both the posts and the surrounding concrete.

• Moisture Penetration:

Concrete acts as a barrier against moisture penetration. However, this doesn’t mean it’s completely waterproof. If water gets trapped between the concrete and the treated wood post, it can lead to rot or decay, compromising both the wood and the concrete foundation.

• Potential for Cracking:

When poured concrete settles around posts, it can create tension that may cause cracks in the surrounding concrete. This can weaken the structural integrity of the post over time.

So, what’s the best approach? While pouring concrete directly around treated posts might not always be a perfect solution, there are alternative methods to consider:

1. Concrete Encasement:

This method involves creating a concrete “enclosure” that completely encircles the post while leaving a gap between the concrete and the wood. This helps prevent direct contact with the treated lumber, ensuring minimal chemical interaction and reducing the risk of expansion or cracking.

2. Rebar Integration:

For posts that require added support, rebar can be integrated within the concrete foundation. The rebar’s steel bars will help reinforce the concrete surrounding the post, preventing warping and ensuring a stable base.

These considerations must be made when planning your project. If you are unsure about the best way to pour concrete around treated posts, consult a qualified construction professional for advice and guidance on how to make informed decisions about your project.