Retaining Wall Materials for a 20' × 4' Wall
A 20-foot wall 4 ft high is 80 sq ft of face — about 120 standard blocks plus caps and base gravel. Switch the material above for poured concrete, timber, or natural stone.
You'll need
120 blocks
Wall face area
80 sq ft20' long × 4' high
Wall blocks
120Concrete block — standard (≈16×6" face)
Cap blocks
20~12" cap units
Gravel base / backfill
1.0 tons6"-deep leveling base + drainage backfill
Block cost (est.)
$600~$5/block material
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