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How to Build a Boulder Retaining Wall

Boulder retaining walls are not only functional, they're timeless and beautiful as well.

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boulder retaining walls are timeless Watch Video
  • Time

    Two Days

  • Price Range

    $250 - $500

  • Difficulty



Step 1: Determine the Placement of the Retaining Wall

Using a shovel, mark on the ground where the retaining wall will be built, including front, back and sides. Drive long wooden stakes into the ground at each corner. If the distances are greater than 8’, drive additional stakes so that no space is greater than 8’.

Step 2: Determine the Height

Determine the desired height of the retaining wall. Tie the end of a string to a corner stake at desired height. Continue stretching and tying string to all the wooden stakes until you have worked all the way around the wall. Use a string level to ensure that all the heights remain level and constant.

determine desired height of retaining wall

Step 3: Prepare a Trench

Excavate a trench to a depth of 8” that covers the entire base of the retaining wall. Spread approximately 3” of gravel evenly in the hole. Rake to level it out.

Step 4: Build the Wall

When using large boulders, it may be necessary to rent a front loader.

Begin placing the boulders in the trench along the front string line. The largest boulders should be placed on the ground level, as close to each other as possible. Backfill the area behind the boulders with gravel to hold firmly in place.

Place the next row of boulders on top of the first, angling them slightly to the back to give the wall more strength. Make sure the second row of boulders sits over the joints of the first. Continue placing boulders, working from largest to smallest, until the desired height is reached. Backfill the area behind the wall.

the largest boulders should be placed on ground