Retaining Wall Calculator
Whether you’re building your retaining wall for aesthetic reasons or to even out the landscape, this calculator will help you plan and carry out the construction process.
Your Retaining Wall Materials Estimate
Wall Blocks Needed
Base Material
Backfill Material
Drainage Pipe
Detailed Materials List
| Material | Quantity | Notes |
|---|
Why Build a Retaining Wall?
Retaining walls serve both functional and aesthetic purposes in landscaping. They prevent soil erosion, manage water runoff, create usable space on sloped properties, and add visual interest to your garden.
Erosion Control
Retaining walls hold back soil on sloped areas, preventing erosion during heavy rains and protecting your landscape.
Create Level Areas
Transform sloped yards into usable flat spaces for gardens, patios, or play areas with properly constructed retaining walls.
Improve Drainage
Well-designed retaining walls include drainage systems that direct water away from structures and prevent water damage.
Enhance Curb Appeal
Retaining walls add dimension and visual interest to your landscape, increasing property value and aesthetic appeal.
Types of Retaining Walls
Choosing the right type of retaining wall depends on your specific needs, budget, and the characteristics of your property.
Gravity Walls
These rely on their own weight to hold back soil. They’re typically made from heavy materials like stone, concrete, or brick and are suitable for walls up to 3-4 feet tall.
Cantilever Walls
These use an L-shaped or T-shaped base that extends back into the retained soil for additional support. They’re engineered for taller walls and require less material than gravity walls.
Sheet Piling Walls
Thin sheets of steel, vinyl, or wood are driven deep into the ground. Ideal for soft soils and tight spaces where there’s limited room behind the wall.
Anchored Walls
These use cables or other stays anchored in the rock or soil behind the wall. They provide extra strength for the tallest retaining walls or those supporting significant loads.
Pro Tip: For DIY projects under 4 feet, segmental retaining wall blocks are the most popular choice due to their ease of installation and interlocking design.
Step-by-Step Retaining Wall Construction
Building a retaining wall requires careful planning and execution. Follow these steps for a successful project:
1. Planning and Design
Determine the wall’s purpose, location, and dimensions. Check local building codes—many areas require permits for walls over 3-4 feet. Use our calculator to estimate materials.
2. Site Preparation
Clear the area of vegetation and debris. Mark the wall’s layout with stakes and string. Excavate a trench for the base material.
3. Base Installation
Add and compact a base of crushed stone or gravel. This provides a stable foundation and aids drainage. The base should extend beyond the wall’s footprint on both sides.
4. First Course Installation
Lay the first row of blocks, ensuring they’re level and properly aligned. This course is critical—any mistakes will compound as you build upward.
5. Subsequent Courses
Continue adding layers, staggering the joints between blocks. Some systems require pins or adhesive between courses for stability.
6. Backfill and Drainage
As you build, add drainage gravel behind the wall and install drainage pipe at the base. Proper drainage is essential to prevent water pressure from building up behind the wall.
7. Finishing Touches
Install capstones on top of the wall for a finished look. Backfill with soil, add topsoil, and plant vegetation to help with erosion control.
Safety Note: Retaining walls over 4 feet tall should be designed by a professional engineer. Improperly built walls can collapse, causing property damage or injury.
Common Retaining Wall Mistakes to Avoid
Even experienced DIYers can make errors when building retaining walls. Avoid these common pitfalls:
- Inadequate drainage: Without proper drainage, water pressure builds behind the wall, leading to failure.
- Poor base preparation: A compacted base is essential for wall stability—don’t skip this step.
- Ignoring local regulations: Always check building codes and obtain necessary permits before starting.
- Underestimating materials: Use our calculator to ensure you purchase enough blocks and base material.
- Building too high: Most DIY walls should not exceed 3-4 feet without professional engineering.
- Poor backfilling: Use appropriate drainage material behind the wall, not just excavated soil.
By using our retaining wall calculator and following proper construction techniques, you can create a beautiful, functional wall that will last for years.