Last Updated on December, 2024
Are you looking to install a fence post? One of the most essential steps in this process is mixing concrete to hold the fence posts in place. Whether it’s a rail fence or a mailbox post, a strong foundation is vital for the stability and lifespan of the fence.
In this article, you will learn everything you need to know to install and set fence posts in concrete.
Quick Summary
- For setting fence posts, you can either buy pre-mixed concrete bags (60 kg per post for a 100-meter fence) or mix your own using sand, gravel, and cement in a 3:2:1 ratio, which can be a more economical choice.
- Begin by digging a hole, adding gravel at the base, and mixing concrete to a smooth consistency. Pour the mixture around the post and use bracing to keep posts straight as the concrete cures.
- Concrete is more stable than using packed dirt alone, can be used year-round (even in frost with additives), and using moisture protection for wood posts can prevent rot.
How to Mix Concrete for Post and Rail Fencing?
The materials you would need for installing a rail or fence post are a proper concrete mix and water. How much it would cost to mix concrete would depend on the size and scope of the project site.
If you are installing the fence on your own, you can choose from two options to acquire the materials. You could purchase a pre-mixed bag; these come in 20kg packs and cost $12, depending on the hardware store.
You will need 60 kg of concrete mix or 3 bags per fence post. A 100-metre fence would need 35 posts, which would sum up to $1,260 for 105 bags.
The other option would be to buy the material in bulk and combine it yourself. You can purchase sand, rock, crushed stone, and general concrete dry mix.
The ratio to mix is 3:2:1 which is sand:gravel:cement, after which you should add water until the mix is consistent. Do not add too much water.
Depending on the cost of your local supplier, mixing your concrete for 35 posts would add to roughly $466.
Useful guides:
Steps for Mixing Concrete
When using a fast setting concrete, you must prep the area. First, dig a hole into the soil where you want to position the fence, using a shovel or a post-hole digger. Before you dig, contact your local utility company to confirm the locations of any utility lines to avoid damaging them.
When using ready-mix concrete, it is fairly straightforward; you only need to add water and pour it into the post hole.
If you are mixing the concrete on your own, you must measure out the materials you need. You can use a shovel or a bucket to measure the right amounts of cement, sand, and gravel.
Afterwards, you can thoroughly combine the dry ingredients in a wheelbarrow with a shovel until you get one form.
Next, add water slowly into the dry concrete mix, combining it until you reach the desired consistency. The level of water to add will depend on the quantity of dry concrete mix you use.
Ensure you mix the concrete thoroughly until it is smooth and has no lumps.
Then, before you pour the mixed concrete, add a few inches of gravel to the bottom of the hole. This keeps the bottom of the post from sitting directly on a wet surface. Make sure the concrete mix is distributed evenly while filling the hole.
To ensure all the posts are straight when you pour the concrete mix into the ground, place a tube form in the hole and set the post into the form. You can also use a level to do this. Once the posts are set, brace each post over a few days to let the concrete cure.
Debunking Myths on Concrete Fence Posts
One common myth is that the dirt from the hole in the soil works just as well as concrete. While reusing the dirt and tamping firmly around the posts is great for temporarily securing, concrete is more solid and long-lasting.
Using dirt may not be structurally suitable as the posts will start leaning after strong winds.
Another myth is that concrete will rot out wood fences over time. There is some truth to this, but there are methods you can use to extend the lifetime of the posts indefinitely, such as using a moisture wrap at the bottom of the post to prevent moisture from contacting the wood.
Another popular myth is to set rails when the ground is not frozen. This is not true. You can set posts all year around, even with a frost line, by adding calcium carbonate to the concrete when mixing. This helps retain heat and speeds up curing.
