Calculate Retaining Wall Materials & Cost
Estimate blocks, gravel, and cost for retaining walls by height and length. Includes drainage requirements.
Retaining Wall Costs by Material
Concrete blocks (most popular): $15-25/sq ft installed, $8-15 DIY. Natural stone: $25-50/sq ft — beautiful but heavy and labor-intensive. Timber: $15-25/sq ft — easy DIY but rots in 10-15 years. Poured concrete: $30-50/sq ft — strongest but requires forms and expertise. A 30-foot long, 3-foot high block wall costs approximately $1,500-3,000 DIY or $3,000-6,000 professionally installed.
Critical: Drainage Behind the Wall
The #1 cause of retaining wall failure is water pressure. Every wall over 2 feet needs drainage: perforated pipe at the base, 12 inches of drainage gravel behind the wall, and landscape fabric to prevent soil from clogging the gravel. Without drainage, water pressure builds behind the wall and eventually pushes it over — often years after construction. This is the most common and expensive DIY mistake.
A properly built retaining wall with drainage lasts 50-75 years. A wall without drainage lasts 5-15 years before failing. The drainage materials cost $200-500 extra on a typical wall — less than 10% of the total project cost. Skipping drainage to save $300 guarantees a $3,000+ rebuild in a decade. Always include drainage.
