How Deep to Dig Fence Post Holes

The depth of your post holes is the most important factor in the stability of your fence. If you do not get the post holes deep enough, there is a greater potential that your fence can be blown over. There are different opinions on just how deep the post holes should be. Another important factor to consider when digging post holes is knowing where cable lines and gas lines are located. These lines are typically run underground, and they can easily be cut with a shovel or an auger. Before ever digging your fence post holes, call your cable company and gas company. The cable and gas companies will come to your home and mark exactly where the lines are located with flags and spray paint. This will help you to avoid interrupting services or potentially putting yourself in danger.

Tools

Post lengths for fences start at 8 feet long; they start at 4 inches by 4 inches in diameter. Posts can also be purchased in greater lengths for digging deeper holes. The average height of a fence panel is 6 feet, and the average length of each fence panel is 8 feet. Post holes can be dug with a shovel, or you can use an auger. An auger is a drill like machine that is more easily capable of digging out post holes in hard ground.

Width

The width of your post holes should be at least a minimum of 10 inches wide. This width will allow adequate room for concrete to be poured into the holes. Not all fence installers use concrete to set the posts, but the vast majority do. Concrete provides the most strength for your posts. There are some fence builders that will refill the holes with the dirt that was removed from digging, and with rock. This procedure does make it easier to replace a post if it should happen to break or split.

Panel Post Depth

The minimum depth that you should dig your fence post holes is 2 feet. The maximum depth that you should consider digging the post holes is 3 feet deep. The deeper you dig the holes, the more stability your fence has, but you must also purchase longer posts. You will also need to trim off 1 foot in length to accommodate the height of the fence panels.

Post Hole Depth for Gates

The minimum depth for your gate posts is considered to be 32 inches. The reason for this depth is that the posts must be able to handle the weight and the movement of the gate. Concrete must also be poured into the post holes. The movement of the gate will loosen your posts--and cause them to lean or eventually break--if you do not concrete them in place.

Concrete

Your concrete should be a gravel mix. It can be purchased at the same place you purchase your fence posts. Your supplies are usually bought at your local home remodeling store. Concrete for fence posts typically comes in 40 and 60 pound bags. For fence post holes that are 2 feet deep use at least one 40 pound bag of concrete. For post holes that are 32 inches deep to 36 inches deep, use a 60 pound bag of concrete.

References

• Post Hole Depth
• Auger