Estimate blocks, backfill gravel, and total cost for your retaining wall project.
Common retaining blocks are 16" x 6" (or 8").
Footing: Always bury the first row of blocks below grade (usually 6-12" deep) to anchor the wall and prevent sliding.
Drainage: Place perforated drain pipe behind the wall at the base of the backfill and cover it with gravel to prevent hydrostatic pressure.
Setback: Most retaining wall blocks are terraced. Each row is usually set back 1-2 inches from the row below.
It depends on your local codes and wall height.
Backfill is the material placed behind the wall. You should not use heavy clay or dirt directly against the blocks, as it holds water and creates pressure.
Use clean crushed gravel (3/4" clean) starting 12" away from the wall face to allow water to drain.
Dry gravel weighs approximately 2,800 to 3,000 lbs per cubic yard. This calculator uses an average of 2,900 lbs (approx 1.45 tons) for weight estimates.