How To Build A Wood Retaining Wall With Deadman

This is a wonderful tutorial detailing how to build a wood retaining wall with deadman.

What is a Deadman

A deadman is a concrete block that is buried underground, typically in conjunction with a steel post. It is used to support the retaining wall and provide additional stability in case of earthquakes or heavy winds. A deadman can be used on its own as well, but it should not be used as the only support for a retaining wall unless you are building an extremely small wall. If you do choose this option, it’s best to build a small section of your wall first before adding any more supports or continuing construction.

Sizes and materials vary by supplier; however, most deadmen are between 12-24 inches long and 8 inches wide, with varying thicknesses depending on what type of material they are made from (concrete blocks have thicker sides than wood posts).

How to Build a Wood Retaining Wall With Deadman

  • Use a level to make sure your posts are straight.
  • Use a shovel to dig a trench.
  • Fill the trench with gravel and sand. It’s important to use a level so that it’s all even—you don’t want one side of your wall slanting in or out more than the other

1. Mark the location

Before you start digging and building, you need to make sure that you know where everything is going to go. Start by marking the location of your wall. You can use stakes or flags (or even a string) if there are any obstacles nearby that could obstruct your measurements or interfere with digging in certain areas.

Next, mark where each post will go in relation to the location of your wall and any other existing structures on your property: buildings, trees, fences. The posts should be spaced out evenly between 6-8 feet apart from one another; this distance will depend on how wide the wall will be and what kind of materials you use for it (i.e., retaining boards vs bricks). Make sure not to put them too close together because then they may end up being difficult for us later on when we install our sheathing boards alongside one another; likewise with putting them too far apart as well – doing so would mean having too much space between slats which could lead down into problems later on down pike when we need some place else where we can rest our heads while getting some shut eye during those long nights working hard at making sure everything stays nice & tidy around here…so remember: keep those posts nice & close together

2. Mark the corners

Mark the corners of your wall by measuring, marking and digging a trench.

  • Mark each corner and make sure that they are square, at right angles to the ground and level with each other. The easiest way to mark them is with stakes in the ground at each end of your location for the wall (A).
  • Dig a trench along all four sides of your four-foot wide area (B), making sure it’s at least 1 foot deep and 2 feet wide. If you have access to solid ground below your soft soil surface, dig down as far as possible until you reach it; if not, dig down just far enough so that there won’t be any water pooling around or under your retaining wall when it rains or snows (C).

3. Dig the trench

The next step is to dig the trench for the deadman. To do this, use a shovel to dig a trench that is 1.5 times the width of your deadman and as deep as it is tall. If you have 4-foot long deadmen, you will need to dig an 8-foot long trench. The width should be equal to half of its height (i.e., if your deadman is 2 feet tall, then your trench needs to be 1 foot wide).

4. Fill the trench with gravel and sand

Now that you’ve got the trench dug and the forms set, it’s time to fill it with gravel and sand. You’ll need a 1:2 ratio of gravel to sand when creating your retaining wall. In other words, for every 2 cubic feet of gravel you use, use 4 cubic feet of sand. Your trench should be filled with at least 2″ of this mixture (you can go higher if you want). Before shoveling in the mixture, make sure to level out each layer with a trowel or shovel so that it sits evenly inside the trench walls.

If you’re building a long retaining wall like ours is currently doing—and if you have enough manpower—consider filling one side at a time instead of all four sides at once! This will make your life much easier when leveling out each layer because there won’t be as many layers sitting right up against each other yet (which often makes leveling more difficult).

5. Attach your posts to the deadman

Attach your posts to the deadman with lag screws or concrete nails, depending on what kind of posts you have. If you’re using 2x4s and wooden posts, use lag screws. If you’re using metal T-posts, use concrete nails. To attach the posts together and to the deadman, make sure there’s at least 3 inches of overlap between each post and one another (the same goes for attaching them all together).

If you want a more permanent solution—and if your soil is soft enough that it doesn’t matter if they sink into it—you can also pour concrete into holes drilled in both ends of each post before driving them in place onto top of the deadman

6. Install your deadman in the trench

When installing your deadmen, the first step is to dig the trench for your wall. The trench should be wide enough and deep enough to accommodate both of your deadmen, so make sure you measure correctly

Next, place one end of each deadman into the bottom of its respective trench. You will want to ensure that these pieces are at least two feet below grade level and two feet away from either side of their corresponding trenches. This will ensure that they don’t move around while being installed or when finished with construction

7. Cut and attach your slats

If you’re using a circular saw to cut your slats, be sure to use a guide so that the blade is aligned with the post at all times. Use a nail gun to attach the slats in place. Once each slat is nailed into place, use a level and check that it’s straight.

A wooden retaining wall with a deadman is an incredibly strong structure that will last for many years with minimal maintenance.

If you are considering building a wooden retaining wall with a deadman, you should know that it is an incredibly strong structure. A deadman is one of the strongest and most stable forms of support for any type of retaining wall. They are easy to build and maintain and will last for many years with minimal maintenance. Wooden retaining walls with deadmen can also add value to your property by increasing its size, adding privacy, or both


We hope this guide has helped you learn more about building a wooden retaining wall with a deadman. If you have any further questions, please feel free to reach out.

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