How to Dig Post Holes and Install Posts

  • 01 of 10

    Measure by Measure

    digging a post hole for arbor project
    Dig a hole about 1 foot deep. Photo © Lisa Hallett Taylor

    The Goal: To install a somewhat flimsy pre-fabricated wood arbor into the ground to ensure stability. The arbor's four posts do not provide extra space to sink posts deeply into the ground with concrete. We will need to dig holes about 1 foot deep, mix concrete in a wheel barrow, and pour it into the holes. This arbor can be used as a transitional structure linking two outdoor spaces, or could be installed against an outdoor wall at a condo or used as a privacy screen once it's covered with plants and vines.

    While this is for a pre-fabricated arbor, you can use this tutorial for decks, fences, gazebos and other outdoor structures.

    Start off the project by measuring center lines of each post to determine where to dig holes for a total of four measurements for four holes. Each hole should be approximately 1 foot in diameter and 1 foot deep.

    Continue to 2 of 10 below.
  • 02 of 10

    Metal Post Anchors

    Use metal post anchors. Photo © Lisa Hallett Taylor
    Embed the anchors into the concrete, eliminating the need to sink the posts in the concrete. We purchased fairly shallow anchors because the arbor will only support the weight of vines. If this was for a fence or deck, you'd want deeper holes for longer, stronger post anchors.
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  • 03 of 10

    Saddle Posts

    Spacing anchor on post. Photo © Lisa Hallett Taylor
    Saddle the posts into the anchors. You want to have an air space between the bottom of the post and the saddle so that it doesn’t retain moisture and has a way to dry. To do this, we used scraps of floor tiles approx 1/4" thick. You can also use 1/4” or 3/8” plywood scrap.
    Continue to 4 of 10 below.
  • 04 of 10

    Here's the Drill

    Drill corresponding holes in posts. Photo © Lisa Hallett Taylor
    Drill corresponding holes. Some anchors have holes that allow them to be nailed into the posts, but for extra reinforcement, drill the holes and bolt them in.

    After drilling holes in posts, attach the anchors securely with purchased fasteners. Place a flat washer on each side of the hole and a lock washer on the end where you install the nut. The lock washer will ensure that the nut won’t back out.

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  • 05 of 10

    Anchored Tight

    Bolt anchor into post. Photo © Lisa Hallett Taylor
    At this point, the anchor is tightly bolted into the post.
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  • 06 of 10

    Measuring the Distance

    Measure from center lines of each post. Photo © Lisa Hallett Taylor
    Since this particular arbor is somewhat flimsy, we need to determine the top width of the arbor so we can clamp the bottom posts at the same distance so that the arbor is squared up. Measure top of arbor from center line of each post.
    Continue to 7 of 10 below.
  • 07 of 10

    Clamp for Solidity

    Use C-clamps on 2x4s. Photo © Lisa Hallett Taylor
    Mark the center lines on the 2x4s and clamp each post to that center line mark with a C-clamp. This way we now have a solid, squared structure that can be positioned over the holes to prepare to pour the concrete.
    Continue to 8 of 10 below.
  • 08 of 10

    Get Support

    Use supports to suspend arbor over holes. Photo © Lisa Hallett Taylor
    Suspend arbor over holes by placing bricks, 2x4s or, in this case, pieces of broken cement and 2x4s. The goal is to use the support materials to space the arbor in increments until it's level and square to the ground. Use the clamped 2x4s from Step 7 as a basis for leveling horizontally and the posts themselves to level vertically. Add or remove spacers until you achieve proper alignment.
    Continue to 9 of 10 below.
  • 09 of 10

    Mix and Pour Concrete

    Pour concrete into hole. Photo © Lisa Hallett Taylor
    After double-checking your measurements and levels, add water to concrete mix per directions on the bag. Use a large bucket or wheelbarrow to mix the concrete. When the concrete reaches the desired consistency, which should be like an extra-thick milkshake, pour in holes. Wait approximately 24 hours or whatever the directions say on your concrete mix.
    Continue to 10 of 10 below.
  • 10 of 10

    The Finished Project: A Safe and Sturdy Arbor

    The finished product: a beautiful, stable arbor. Photo © Lisa Hallett Taylor
    Remove spacers, unclamp 2x4s last used in Step 8, clear away loose concrete. Fill holes with dirt and proceed to put in groundcover, pavers, plants, or whatever else you have in mind. Enjoy your arbor, knowing the posts have been imbedded securely into the ground. Congratulations -- you did it!