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How to Calculate Gravel for a Retaining Wall

Cleveland Van Cecil

Retaining walls are used in the garden to hold back crumbling soil. They help prevent soil erosion and mud slides. Building a retaining wall stronger requires adding ample drainage behind the wall unit. Gravel provides a porous material for water to run down behind the wall and drain away. Calculating the correct amount of gravel required will prevent unnecessary costs or delays when waiting for additional material.

Getting the gravel amount right involves accurate calculation.
  1. Mark out the area for your wall with stakes and string.

  2. Set down the blocks for your wall 12 inches out from the dirt hill you are using the wall to retain.

  3. Measure the length of the wall.

  4. Measure the width of the wall, measuring from the back of the blocks to the dirt wall.

  5. Determine the height of the wall.

  6. Multiply the length, width and depth of the wall. Divide the number by 27 to get the cubic yards of gravel required for your wall.