- 1). Lay a piece of string along the ground and arrange it in the shape you want your wall to be. Your landscape retaining wall should consist of straight lines and gradual curves.
- 2). Mark the line by pouring flour along it.
- 3). Dig a trench in the ground that marks the course you want your wall to take. The trench should be a bit wider than the stackable blocks you are using and at least three inches deeper than their height. Dig the trench as flat as possible.
- 4). Tamp down the trench to level and compress the ground. Pour three inches of gravel into the trench and tamp that down as well.
- 5). Place the first stackable concrete block at one end of the trench. Place a level on top of it to check its level side to side. Then, check it front to back. If it does not sit evenly, remove the stone, add a bit of gravel to the low side of where it sits, and put it down again. Continue to adjust the stone until it sits level.
- 6). Hammer a wooden stake into the ground on the outside of the first stone you placed. Hammer a second stake at the far side of the trench.
- 7). Tie one end of a string to the first stake so that it grazes the top of the stone. Stretch the string to the second stake, and thread a level onto it near the end. Move it up and down until it is level, then remove the level and tie it to the second stake.
- 8). Lay a stone next to the first stone and check it with the level; add or remove gravel to level it. It should sit level front to back and side to side, and be even with the top of the string.
- 9). Remove the string and the stakes. Lay a second course of stones on top of the first so that the lip of the second stone fits right behind the edge of the first. Stackable concrete walls will slope back slightly as the lips interlock with the stones below to form a stable wall.
- 10
Continue adding courses until the wall is completed.