Best Fence Installation: Why Your Fence Starts at the Hole
The first step in a fence installation is digging the holes for the fence posts. While this initial step is seemingly simple, it’s also the foundation of your entire finished fence. Failure to dig the postholes just right can result in a collapsed fence installation. Before you dig, therefore, it’s important to consider the ideal alignment, the required depth of your postholes, and the different methods used for digging. No pressure, right?
Posthole Placement and Alignment
One of the most important aspects of posthole placement is the linear alignment. What would the neighbors think if you had a crooked fence? For a basic privacy fence installation with posts that are all the same size, you can use the traditional post placement: A post at each corner, and additional posts placed 8-10 feet on center. You can simply use stakes to mark the locations of the posts, and tie a line to each corner stake.
You’ll need to make different preparations, however, if you’re using posts that are different sizes. First, find the location of the first corner post and paint a circle on the ground that has the same diameter as the post. Go to the opposite vertical or horizontal (not diagonal) corner of the fence and repeat the same process. Then stretch a line between the outer edges (not the centers) of the two corner posts. Repeat this process with the remaining corner posts. You should mark the positions of the posts in order of size, starting with the smallest. Keep in mind that as the sizes of the posts increase, you’ll have to offset the marks so the outer edges of the posts line up evenly with each other.
If the in-line t-posts in your fence installation differ in size from the corner posts, use a different color of paint to mark each post’s location on the ground. This trick will help you remember to use a different-sized posthole digger or auger for each posthole.
The depth at which you’ll need to dig your postholes depends on where you live. The ideal depth is 48 inches (4 feet) below the frost line. Otherwise, freezing weather can cause structural damage to your fence over the long term. If the frost line is 36 inches (3 feet) below ground, for example, you’ll need to dig a hole that’s 84 inches (7 feet) deep. If you’re not sure where your frost line is, ask a neighbor or your city planner.
If the ground in your area never freezes (like in southern Florida), you can simply dig the posthole 4 feet deep. If you’re using 4×4 posts, the diameter of your postholes should measure 10-12 inches. For best results, use a spirit level to make sure the bottoms of the postholes are level so the posts and the rest of your fence installation will be plumb and aligned correctly.
Tools for Digging Postholes
There are two basic tools for digging postholes – a posthole digger and an auger. A posthole digger is a manual tool that looks like two small opposing shovels that are connected by a fulcrum. Spread the handles apart to separate the shovels, place the digger into the ground and bring the handles back together to make the posthole digger grab some dirt. Bring the posthole digger out of the dirt, empty the contents you just acquired and repeat. A posthole digger is an economical (and tolerable) tool to use if your fence installation isn’t that big and the postholes aren’t too deep.
For bigger projects, however, it’s worth your while to use an auger to dig out the postholes. Augers are like big drills that come in a variety of sizes. If you don’t have an auger and don’t have a friend who owns one, see if you can rent one from a local hardware store or tool exchange. If neither of these tool options seems feasible to you, contact a cedar fencing contractor to do the measuring, spacing, posthole digging and heavy lifting for you.
The most important aspect of a fence installation, aside from the postholes, is your safety and the safety of your family and neighbors. Before you begin to dig, call your local utility companies to find out if there are any underground electric, gas or water lines along your fence line.