Gravel: Filling the hole with gravel will help to support the fence post. This method is stronger than using dirt, but not as strong as using cement. Sand: Filling the hole with sand will help to support the fence post. Like gravel, this method is stronger than using dirt, but not as strong as using cement.
You can strengthen loose posts by adding more foam and covering it with dirt to force the foam into gaps as it expands. But all in all, you're probably better off choosing concrete when you need strength.
It works so well, in fact, that in mild climates, builders sometimes elect to set fence posts with gravel alone. While that approach makes sense in certain situations, for a lasting installation, experts are more likely to specify a combination of gravel (for drainage) and concrete (for much-needed stability).
If your leaning post has rotted, or you need to install a new one, consider using a ground spike. It's an easy alternative to concrete or foam, and only requires simple tools. Simply drive the spike into the ground with a sledgehammer, checking for level every few hits.
Gravel: Filling the hole with gravel will help to support the fence post. This method is stronger than using dirt, but not as strong as using cement. Sand: Filling the hole with sand will help to support the fence post. Like gravel, this method is stronger than using dirt, but not as strong as using cement.
Stabilize Your Fence Post
You'll first want to dig a few inches of soil out from around the post's perimeter. From there, you can fill the hole with gravel and top the gravel with a rapid-set cement mix. Finally, pound the fence post back into place using a mallet.
While a treated 4x4 may last 10 to 25 years, depending on the wood, the soil, and weather conditions, following the simple steps below could double or triple that number. By comparison, an untreated wood fence post may need replacing in as little as five years.
Dig post hole so diameter of the hole is 3 times the width of the post (i.e., the hole for a 4” wood post should be about 12 inches wide). The depth of the hole should be 1/3-1/2 the post height above ground (i.e., a 6-foot tall fence would require a hole depth of at least 2 feet).
Step 4: Set a layer of gravel on the bottom
This will help with drainage and prevent water from pooling at the bottom of the post. Pea gravel is preferable, but any kind of gravel or small crushed stoned should do the trick. Make sure you tamp down the gravel well, or in other words, make sure it sits compact.
The depth of the post should be a minimum of ⅓ of the height of what's above ground. This means that if you want a 6-foot tall fence, you need at least 2 feet of the post to go below ground. If this was the case, you would need at least 2 bags of concrete per fence post, with each individual bag being a 50lb bag.
Pros. Expanding foam is generally considered more eco-friendly than concrete because it produces less waste. It also sets and cures quickly (in less than 15 minutes) and can be applied in cold temperatures. Expanding foam for fence posts is also lightweight and a smart choice for a DIY since it doesn't require mixing.
That Foam Isn't Going ANYWHERE
The polyurethane foam Liftech uses to complete repairs will last indefinitely – through your lifetime and well beyond. It cures within minutes as a solid, impermeable structure that adheres directly to the concrete. It is not susceptible to fracture or failure.
Most fence posts require anywhere from one to 10 bags of concrete. Actual concrete amounts vary depending on post hole diameter and depth. Account for frost lines and gravel when doing calculations.
As a general rule of thumb, you'll need to place at least 1/3 the height of the post in the ground. For example, a six-foot tall fence will need at least two feet of post in the ground.
Concrete posts are susceptible to chips and cracks, which can cause problems for your fencing. When a small chip or crack appears on the surface, water can travel deep into the post. The water can then freeze in cold conditions (usually overnight), causing the chip or crack to worsen overtime.
A fence is only as strong as its posts. The American Standards for Testing Materials (ASTM) suggests always setting fence posts in cement. One of the most important reasons your fence posts should be set in concrete is to keep them plumb and level over time.
The general rule of thumb when setting a post is that the depth of the post's hole needs to be one-third to one-half of the actual above-ground height of the post. So, a six-foot-high finished post ideally needs to be buried three feet into the ground.
Mix two 50lb bags of concrete with water in a mixing tub or 5-gallon bucket. Add concrete into the hole and around the 4” x 4”. Depending on your climate, let concrete set up for 24 - 48 hours.
Protect your posts with Flex Seal Liquid®! Our thick liquid rubber is perfect for preserving and. protecting outdoor accents like fencing.
Ground-contact pressure-treated lumber can be used either above ground or in contact with the ground. Has twice the level of chemical retention and protection compared to above-ground treated wood. Must be used when lumber is less than 6 inches from the ground or has poor ventilation.
Add Gravel to the Hole
This will provide a solid base for the post, but will also allow water to drain away from the post instead of accumulating in the hole. Make sure to tamp down the gravel with a scrap piece of lumber so that the fence post can be installed on a firm, flat base.
Set the post in the ground and surround it with around 4 inches of gravel to encourage drainage and stability. Pack another inch of soil around the top of the gravel to encourage the post to remain level. Test the post with a level to ensure it is plumb and sits properly in place with the rest of your fence.
To set a post in gravel or soil, tamp down a 2-3 inch (5-8 cm) layer of gravel and insert the post. Then, add and tamp gravel or soil into the hole until it's filled. To set a post in concrete, tamp down a 4-6 inch (10-15 cm) layer of gravel and insert the post. Brace it with stakes, then shovel concrete into the hole.