Should Wood Posts Be Set in Concrete?
Setting wood posts in concrete is a common practice to ensure stability, longevity, and resistance to movement, especially for applications such as fences, decks, and structures that require a strong foundation. However, it is crucial to follow proper installation techniques to achieve optimal results.
Benefits of Setting Wood Posts in Concrete
Stability: Concrete provides a solid foundation that helps prevent the posts from shifting or leaning over time. This is particularly beneficial in areas with high winds or unstable soil, ensuring that your structures remain stable and secure.
Longevity: By protecting the bottom of the wood posts from moisture and soil contact, concrete can significantly reduce the risk of rot, thereby extending the lifespan of the posts. This is especially important in environments where wood is prone to moisture damage.
Resistance to Movement: Concrete anchors the posts in place, making them less susceptible to movement caused by frost heave or ground settling. This ensures that the structure remains firm and stable throughout the seasons.
Considerations for Setting Wood Posts in Concrete
Drainage: It is essential to ensure that the concrete is shaped to allow water to drain away from the post. Standing water can contribute to rot even if the post is set in concrete. To prevent water from accumulating, the concrete should be shaped to provide proper drainage.
Post Treatment: Using pressure-treated wood or naturally rot-resistant species like cedar or redwood is recommended. Pressure-treated wood is a common choice as it is specifically designed to resist decay and insect infestation. For naturally rot-resistant wood, species like cedar or redwood are excellent options due to their natural resistive properties.
Installation Depth: In colder climates, posts should be set below the frost line to prevent heaving. This general rule is to bury one-third of the post's length in concrete. This ensures that the post remains stable and protected from the ground's movement due to freezing and thawing cycles.
Alternatives to Using Concrete
While setting wood posts in concrete provides significant benefits, there are also alternative methods to consider:
Joining Posts with Metal Brackets and Bolts: For a more aesthetically pleasing installation, metal brackets and bolts can be used to attach the post to the concrete. This method can improve the appearance of the installation and ensure a strong connection without the need for visible concrete.
Mixing Concrete for Replacement: Scott suggests using concrete below ground and a few inches above ground. This method allows you to fill a hole with concrete, set the appropriate bracket in the hole supported by temporary cross pieces to hold the post above ground and reduce rot.
Using Expanding Foam: For a more cost-effective and easier solution, you can use expanding foam mix from a local big box store. This method is less expensive and easier to implement. Just be sure to taper it away from the post to prevent water from being trapped next to the post. This method is also easier to remove if necessary.
Conclusion
Setting wood posts in concrete is generally a good practice for added stability and longevity, provided that proper installation techniques are followed. However, depending on your specific situation and desired aesthetic, alternative methods such as the use of metal brackets, trench filler, or expanding foam can be effective. It is crucial to prioritize stability and longevity to ensure that your structures remain safe and secure over time.