Can You Erect Fence Posts in Wet Clay Soil?

large farm style gate with fence posts in wet clay soil

Fencing can be a fun DIY, especially when the weather's nice. Soil types can pose a challenge, though, and wet clay is one of the trickiest. To make a fence firm and durable in wet clay soil, you'll need to dig and pour a deep concrete base.

Consequences of Inadequate Installation

It is possible to erect fence posts in wet clay. However, without proper procedures, you risk an unstable fence that can easily get damaged by adverse climatic conditions. Even slight pressure can topple posts in wet soil if they're not sufficiently anchored, putting your fence at risk.

So this means you're going to want to use concrete, but you might experience some challenges with this, too, especially if the ground is moist to the point of being soupy, which can prevent cement from setting.

Post Tricks for Wet Conditions

Setting wood posts in concrete with no special treatment can lead to rotting in wet soil. To get around this problem, dig your holes about three to five inches deeper than you otherwise might, then put gravel at the bottom for fence posts to rest on. Experts recommend you backfill the bottom third of your post holes with tamped gravel.

If you're using concrete, go for a dry mix. If you're worried about it setting properly in wet conditions, you can mix the concrete with a small amount of calcium chloride, though this method is less effective in warmer areas.

If you do add calcium chloride, take care to follow the specific instructions of the product you apply. Adding a handful of it helps speed up the time it takes for concrete to set. The faster your concrete sets, the less likely it will be impacted by the wet conditions.

Step 1 - Dig

post hole digger removing dirt from a hole

Start by digging holes using your hole digger. Make sure that every hole is slightly over 20 inches in depth and with a width of approximately 6 inches. It is recommended that the hole penetrates below the frost line by several inches. As mentioned earlier, make sure that each hole is three to five inches deeper than normal.

Step 2 - Backfill

The second step involves filling up the holes you dug with a trusty shovel. It is important to ensure that you backfill the bottom third of every hole with tamped gravel.

Step 3 - Prep Concrete

In this step, you should start preparing your concrete mix. The best way to do so is by mixing concrete with water. Then, stir it gently with a shovel in a wheelbarrow. After preparing the concrete, add it to every hole.

square hole in dirt with wet cement

Step 4 - Insert Post

In this step, take your fence post and put it inside the hole containing concrete. Use any kind of force to secure it in the hole and ensure it gets all the way down. The deeper the post goes, the stronger your fence will be. Repeat this process for every post hole available.

Step 5 - Level

Lastly, level and balance out all the posts before concrete sets. Make sure that every post is in correct alignment with one another and adjust properly. You are free to add more concrete if you feel it's not enough. If you do everything as directed, the concrete should set within 24 hours.

Possible Ways of Dealing with Shallow Water Table

There are several ways of dealing with a shallow water table. Apart from the directions above, there are ways you erect fence posts in wet conditions. However, it depends on how wet the conditions are and the soil drainage. Two potential approaches you can try are digging deeper holes and using metallic fence posts.