# How much gravel do I need to fill a post hole?

## How much gravel do I need to fill a post hole?

How much gravel do I put in the hole? You should put approximately 2″ to 4″ of gravel in the bottom of the hole making sure that the Post stands 6′ 4″ tall from the ground to the top of the post. How wide should the holes be? An 8″ diameter wide hole should be dug for the posts to be inserted for a solid Fence.

## How do you calculate concrete post holes?

Calculate Concrete Volume With the volume of the submerged post and the volume of the hole figured out, subtract the post volume from the hole volume, and you will have the volume of concrete needed for each hole. Simply multiply that amount times the number of posts to get a total quantity.

**Do you need to put gravel in post holes?**

DO Employ a Base Gravel Layer If a fence post fails without any sign of a pest infestation, it’s likely that the failure was caused by moisture that rotted the wood over time. Once you have added gravel to a depth of three inches or so, use a piece of scrap lumber to tamp down the layer.

### How big of a hole do I need for a 4×4 post?

12 inches

The diameter of your post hole should be three times the diameter of your post. So, if you’re planning on using a four-inch round or 4×4-inch square post, your post hole will need to be 12 inches in diameter. For a six-foot-high fence post, we would need a hole that’s 36 inches deep and 12 inches in diameter.

### How much concrete do I need for fence posts?

In terms of the ratio to use for a concreting fence posts, the best mix is a mix of 1:2:4 (1 cement, 2 sand, 4 aggregate). Concrete is always best mixed using a cement mixer to ensure it’s even, but if you only need to mix a little, hand mixing is ok (see mixing concrete project above for tips on how to do this).

**What do you backfill a post hole with?**

The trick is to use medium-size drainage gravel instead of pea gravel. The individual rocks in drainage gravel wedge against one another to mimic concrete. Backfilling with soil is usually only appropriate for a post-and-rail fence that isn’t heavy and doesn’t create a windbreak.

## Do I need gravel under concrete fence post?

Concrete provides a strong foundation for wooden fence posts, but can rot them more quickly. Setting them in dirt, with or without gravel or crushed rock depending on your soil type, can help the posts last longer before going rotten.

## How to calculate how much gravel you need for a yard?

Our calculator uses the formula to convert and calculate: width/3 x length/3 x depth/36 = amount of gravel in cubic yards. Since our calculator takes the effort out of finding out how much gravel you need, you do not need to remember the formula or how to make the calculation manually.

**How to calculate the volume of a post hole?**

Calculate the hole volume. Hole radius (3x post radius): 3 x 0.1458’ = 0.4374’ Volume of post hole: ( 0.4374’)2 x π x 2’ = 1.2026 cubic ft.

### How to calculate the volume of a gravel foundation?

The volume of a figure with a round foundation is its height times the area of its foundation. To calculate the foundation area the calculator needs its diameter, since the formula is π x r 2, where r is the radius, or diameter/2. Again, the gravel calculator will do this math for you.

### How can I find out how much concrete I need for a post hole?

Use the post hole estimator to quickly find out how much concrete you will need to set your fence posts. Enter your post and hole dimensions in any units. The calculator will give you the results in cubic yards and the number of pre-mixed bags of concrete (40 lb, 60 lb, and 80 lb bags).