CountryByNet.com Forums :: Small Retaining Wall

When a bank of dirt falls, usually the top 1/3rd or so starts to slide first. (The weight of that material on the pile holds the bottom part of the pile in place. ) After the top part is gone, then the lower material will begin to move. The wall works by being strong enough to remain in place against the weight of the moving dirt. You can accomplish this through weight of materials, increasing the base, or added bracing.

The taller the pile of material, the more weight will be moving when the top part begins to slide. The reason I would choose 4' is to ensure that the wall will stay where I put it when that top 1/3rd starts to move. The materials you have chosen are not individually very heavy, so I would opt for more below the ground in order to try to keep the wall vertical. (Remember that rainfall, lawn mowers and just people walking around can add to the weight of the material trying to move.)

There are several other ways to strengthen the wall that would not require as much depth on the poles. You can add a curve, or a "v" shaped pattern like VVVVVV. This makes the wall stronger by making the base wider. You could also slope the wall so it leans back slightly at the top. (If you look at the cement work on overpasses, it is often sloped this way.) Again, this makes the base wider.

When I built my own wall, I used stone. The wall is thicker at the bottom and thinner at the top. It also is curved and leans slightly backward at the top. It is about 5' high. I helped a buddy build his walls using old railroad ties. We stacked his ties to about 4-5 feet and used "T" shaped anchors made of more ties to run back into the bank. Each tie was lagged to the ones beside, above and below it. We then drove stakes into the ground for added support. His wall goes straight up and is the same thickness top to bottom.

Both walls are a minimum 8" thick and have been up more than 3 years with no movement. I would think the block would have more weight and therefore would hold better. You would just need a good footing. Personally I would prefer the look of the treated lumber, and it seems like cost would be about the same.

You might try getting a few boards and building one section of wall. Also, get a few blocks and try drystacking them. (Just stack them up without mortar). See how both hold up and next spring figure out what you'd like to do. That gives you a few months to see how the walls hold up and which you like the looks of. Make sure you get through winter and the rainy season before making a choice.

Steve

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