FAQ: How Much Concrete Do I Need For Fence Posts?

How much quikrete do I need for a fence post?

Remember, the depth of the post hole should be one-half of the above-ground post height. (Example: For a 6 feet above ground post, use a post with an overall height of 9 feet and place 3 feet in the ground). The calculator will indicate the number of 50 lb. bags of QUIKRETE® Fast-Setting Concrete you need.

How much concrete do I need for a 4×4 fence post?

The general rule of thumb when setting a post is that the depth of the post’s hole needs to be 1/3 to 1/2 of the actual above-ground height of the post. So, six-foot-high fence posts ideally need to be buried three feet into the ground. The diameter of your post hole should be three times the diameter of your post.

How do you calculate concrete for fence posts?

Example Fence Post Concrete Calculation

1. Calculate the post volume. Change post diameter to feet: 3.5” / 12 = 0.2917′ Find radius (½ of the diameter):
2. Calculate the hole volume. Hole radius (3x post radius): 3 x 0.1458′ = 0.4374′
3. Calculate concrete volume. Hole volume – post volume: 1.2026 – 0.1336 = 1.069 cubic ft.

How much sand and cement 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).

Is 2 feet deep enough for fence posts?

Project Instructions

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).

Should I use concrete for fence posts?

Concrete is the most secure material for setting fence posts, especially if you have sandy soil. Using premixed concrete rather than dry concrete will ensure ultimate security. While concrete is sturdy, it lacks the drainage of gravel and can trap moisture, ultimately leading to rot.

How long will a treated 4×4 post last in the ground?

The treated post that are rated for ground contact are guaranteed for 40 years.

Can pressure treated posts be set in concrete?

Simply setting the posts in concrete does create a condition that will accelerate rot in the bottom of the posts. With pressure–treated posts, the rot will be slow. Concrete should be poured around the post – no concrete under the post.

How do you keep fence posts from rotting in concrete?

Consider Adding Posts to Concrete

From here, you should fill the hole with about 6 inches of gravel. This will prevent rotting by ensuring that the post is kept dry when water makes its way into the soil. Place the post in the gravel, then fill with a batch of cement until it reaches the top of the hole.

How many bags of concrete do I need for a 10×20 slab?

A 60-pound bag yields. 017 cubic yards, and an 80-pound bag yields. 022 cubic yards. For a 10 x 10 slab, you would need 77 60-pound bags or 60 80-pound bags.

Do you need gravel under concrete?

Whether you pour concrete for a walkway or patio, a strong gravel base is required to prevent the concrete from cracking and shifting. Gravel is especially important in clay soil because it doesn’t drain well, which results in water pooling under the concrete slab and slowly eroding the soil as it finally drains.

How do I keep my post level while concrete dries?

Fill the hole up to a depth of 8 inches from ground level with 1/2-inch drainage gravel. Use rough-cut gravel with sharp edges. It will hold the post better than smooth rock.

Can you put dry concrete in a post hole?

Fast-setting concrete is ideal for setting posts because there’s no mixing—you simply pour the dry concrete from the bag right into the hole, then add water.

How do I put a post in the ground without concrete?

Procedure:

1. Find a concrete surface and lightly tamp your digging iron against it.
2. Remove the turf and topsoil from the site of the post.
3. Dig the hole putting the displaced earth onto the tarp.
4. Pour 4 inches of gravel into the hole.
5. Place the post in the hole.
6. Add another 2 inches of gravel around the base of the post.

What’s the difference between Postcrete and concrete?

Concrete takes several hours or a day or two to set. Postcrete sets in a few minutes, several tens of seconds, even, so you don’t have to support the post for nearly as long as you do with concrete.