Calculator
Enter your project details to get accurate material estimates
Project Details
Material Estimates
Enter your wall dimensions to see material calculations
How to Calculate Retaining Wall Materials
- 1. Measure wall length and desired height
- 2. Choose block size (affects courses needed)
- 3. Calculate courses: Height ÷ Block Height
- 4. Calculate blocks per course: Length ÷ Block Length
- 5. Add drainage, base, and backfill materials
Planning a larger project? Explore ConvertQuick for companion planning tools and scheduling aids.
Installation Tips
- • Compact base gravel in 2-3" lifts for stability
- • Set first course below grade (buried)
- • Step back each course slightly for batter
- • Install drainage pipe at base level
- • Use adhesive on cap blocks to prevent shifting
Frequently Asked Questions
How high can I build a retaining wall without engineering?
Most building codes allow DIY retaining walls up to 4 feet without engineering. Walls taller than 4 feet typically require structural engineering approval and permits. Check your local building department.
Do I need drainage behind a retaining wall?
Yes, drainage is critical. Install perforated drain pipe at the base behind the wall, wrapped in gravel and geotextile fabric. This prevents water pressure buildup that can cause wall failure.
Should I use adhesive on retaining wall blocks?
Adhesive is recommended for cap blocks and the top 2-3 courses to prevent shifting. Lower courses typically rely on weight and interlocking design. Use construction adhesive rated for masonry.
What's the best gravel for retaining wall backfill?
Use 3/4" crushed gravel or drainage stone for backfill. It drains well and compacts solidly. Avoid round river rock (doesn't compact) or fine gravel (doesn't drain).