How to Install a Wooden Post Correctly
Setting a wooden post/ pole in the ground is very important to keep it stable and prevent it from rotting too quickly. Using concrete will help to secure the post, but is not always essential if you are working in very dense soil. When building a fence you need to install the main posts firmly, but the same applies for other poles used for other outdoor structures. Below are some handy tips for what to do or not to do when planting a wooden pole with or without concrete.
Installing a post in soil or gravel
This method can be used if you have very dense soil, but with good drainage. It requires a bit more labour and might be less stable than with concrete, but it is cheaper and the posts can last longer that those set in concrete, as water drains off more easily.
- Use posts made from very durable wood and/or treated wood. It must be suitable for “ground contact”.
- You can also treat the sawed-off exposed ends of the wooden pole with a preservative if necessary. Allow enough time for it to soak in and follow all safety precautions.
- Dig a hole that will allow about a quarter to a third of the post to be in the ground. If you’re planning to just use soil, make the diameter of the hole very close to the size of the pole. If you’re using gravel, make it a bit wider. Keep some of the soil to fill up the hole again later.
- Add gravel into the hole for improved drainage. Stomp it down with a stick or tamping bar.
- Place your post in the hole so that it’s straight and level with the other posts in the fence or structure.
- Get an assistant to hold it steady or secure it with stakes and screws to keep it in place.
- Add crushed stone or soil around the sides of the post to fill the rest of the hole. Tamp/ stomp the stones after each batch. If you want to plant grass around the post, use soil for the last layer.
- Make a small hill at the base of the post which slopes in all directions.
Installing a post with concrete
Concrete may be required if your soil is very loose and sandy and if you need additional stability. It’s advisable to use for gate posts for example, which may need to take more pressure than the other posts in a fence. The one problem with concrete is that it can trap water around the base of the post and cause it to decay faster. This is why it’s important to use concrete in a way that still allows drainage.
- Once again use posts made from very durable wood and/or treated wood. They must be suitable for “ground contact”.
- Dig a wide hole. For a standard fence post the hole should be about 30cm wide and the depth should allow for about 1/3 of the post to be underground. Add extra space below to accommodate the base. You can use a post hole digger or post driver to help create the hole.
- Add about 10-15 cm of gravel to the base of the hole to allow for better drainage.
- Position the post in the hole. Drop two stakes into the soil next to the post. Nail or screw two pieces of wood between the stakes and the post. This is just temporary to keep the post in place until the concrete has set.
- Repeat this process for all posts that require a concrete base.
- Add another layer of gravel around the base of the posts.
- Mix your concrete mixture.
- Fill the rest of the holes around your posts up to soil level.
- Trowel the concrete into a slope shape so that it slopes downwards from the pole. This helps to allow water to run off from the post and stop decay.
- Allow at least three days for the concrete to set before you continue building the fence or putting any weight on the post.
- Seal the gap between post and concrete with a sealant that bonds to concrete and wood.
NB: Do not enclose the base of the pole completely in concrete as this will cause water to collect there and the pole to rot.
Feel free to contact us if you need any more tips or advice on how to set a wooden post the right way. If you need instructions on how to install a whole fence read our article: How to build a wooden fence.
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