How to Build a Retaining Wall: The Complete DIY Guide for Homeowners
April 10, 2025
Retaining Wall 101 Tools, Planning & Prep Work
Building a retaining wall isn’t just a weekend project it’s a landscape transformation. Whether you’re looking to stop erosion on a slope, define a patio, or build a raised garden bed, retaining walls offer structural support and serious style. But before you grab that shovel, a solid foundation begins with planning, prep, and the right tools.
Let’s dig in.
Why Build a Retaining Wall?
Retaining walls aren’t just decorative they serve real functional purposes in both residential and commercial landscapes. Here’s why homeowners across Ohio, Kentucky, and beyond turn to retaining walls for lasting outdoor improvements:
This image is a visualizer created to help you imagine what’s possible. While not actual project work, it reflects the kind of custom outdoor living space Serene Aqua can help bring to life.
Prevent Soil Erosion
On hilly or sloped lots, heavy rains can wash soil downhill and wreak havoc on landscaping. A retaining wall acts as a barrier to hold soil in place, especially after the spring thaw or intense summer storms common in places like Cincinnati, OH or Florence, KY.
Maximize Usable Yard Space
Got a sloped backyard? Retaining walls let you flatten out areas to install patios, gardens, fire pits, or play spaces. By building in terraces or flat zones, you turn a sloped yard into a usable multi-level layout.
Add Curb Appeal & Property Value
When built with high-quality materials and smart design, a retaining wall can visually define your landscape and boost resale value. Natural stone finishes or block systems that match your patio or driveway elevate the look instantly.
Create Garden Beds and Outdoor Rooms
Retaining walls are the foundation for raised flower beds, small retaining planters, and seating walls around patios or fire pits. They make it easier to manage mulch, root depth, and watering while creating defined zones.
Tools and Materials Checklist (What You’ll Actually Use)
Before you begin excavation or stacking your first block, having the right tools and materials on hand will save time, sweat, and mid-project runs to the hardware store. Here’s what you’ll need.
Essential DIY Tools
Tool | Why You Need It |
Shovel | For digging the trench and leveling base. |
Hand Tamper | To compact base gravel properly. |
Rubber Mallet | To adjust block alignment without damage. |
Level (2–4 ft) | Ensures each course is perfectly flat. |
Tape Measure | To measure trench depth, wall length, and block spacing. |
Chisel & Small Sledge (Mini Sledge) | For cutting block lips or shaping edge pieces. |
Circular Saw + Masonry Blade | For precision block cuts (optional but useful). |
Wheelbarrow | For moving gravel and base material. |
Caulk Gun | To apply construction adhesive. |
Gloves & Safety Glasses | Always use when cutting, hammering, or leveling. |
Key Materials for a Block Retaining Wall
Material | Purpose |
Interlocking Retaining Wall Block | Forms the structure — choose style, color, and texture. |
Gravel / Drainage Aggregate | Base and backfill — allows water to drain behind the wall. |
Paver Base (Crushed Stone) | Compacts to form a solid base trench. |
Landscape Fabric | Prevents soil intrusion into gravel, aids drainage. |
Construction Adhesive | Secures top layers and caps for durability. |
Optional: Perforated Drain Pipe | For walls over 24″ — routes water away from structure. |
💡 Pro Tip: Always buy 10% more block than you estimate — this accounts for cuts, breakage, and future repairs.
Choosing the Right Retaining Wall Block System
Not all blocks are created equal. Here are three main styles of block systems you’ll find at local retailers like Lowe’s or Home Depot, or from hardscaping pros like Serene Aqua or Great American Contractors:
Key Materials for a Block Retaining Wall
1. Gravity Wall Blocks (Stackable, No Interlock)
- Rely on their weight to stay in place
- Great for low walls (under 2 ft)
- Easiest to install but less stable over time
2. Interlocking Blocks with Rear Lip or Tongue
- Built-in locking mechanism prevents sliding
- Ideal for DIYers — helps keep walls level
- Most common for 2–3 ft backyard walls
3. Pinned Systems (for Higher Walls or Pro Use)
- Uses metal or plastic pins to reinforce strength
- Better for commercial or multi-tiered builds
- Usually needs engineering plan/permit if over 3–4 ft
🧮 How Many Blocks Will You Need?
- Length of Wall ÷ Length of Block = Blocks per row
- Height of Wall ÷ Height of Block = Number of rows
- Don’t forget: the first row is partially buried!
You can use a retaining wall block calculator to simplify the math or ask your local landscape supplier to assist.
Planning & Marking Your Layout (Like a Pro)
A beautiful retaining wall starts with a smart layout. Here’s how to approach planning — and avoid issues down the line.
1. Use Rope or a Hose to Map Out Curves
Lay a flexible garden hose to define natural curves or free-form designs. This is perfect for raised planting beds or corner transitions.
2. Use Stakes and String for Straight Lines
Set two stakes at each end and stretch string tightly between them. Mark the line with landscaping paint for precision.
3. Mark Wall Depth and Width
Your trench should be 12 inches wide and at least 4–6 inches deep — wider and deeper for taller walls. Always plan for the first block row to be half-buried.
4. Consider Drainage and Downspouts
- Avoid routing gutter downspouts toward the wall
- Ensure there’s natural slope behind the wall for drainage
- Install perforated pipe for walls 24″ or higher
Don't Skip This: Call Before You Dig
In the U.S., always dial 811 or visit call811.com before breaking ground. They’ll mark gas, electric, and water lines for free — avoiding a dangerous and costly mistake.
📌 Permit Tip: In many Ohio and Kentucky counties, retaining walls over 3 feet require a permit or engineer’s approval. Always check local codes or HOA rules.
Step-by-Step: How to Build a Block Retaining Wall Like a Pro
If you’ve completed your planning, ordered materials, and mapped your layout, you’re ready to build. Whether you’re working with interlocking blocks or standard stackable units, a successful retaining wall begins with careful excavation and base preparation. The following step-by-step process will guide you through building a structurally sound wall that lasts for years.
Step 1: Dig the Trench and Prepare the Base
Before laying any blocks, the trench must be excavated correctly to provide a stable foundation.
How Deep and Wide Should the Trench Be?
- Depth: Dig your trench approximately 4 to 6 inches deep, plus the height of the buried portion of the first course of block (usually half of the block’s height).
- Width: Make the trench at least 12 inches wide or twice the depth of the block front to back.
This trench should follow your pre-marked layout, whether curved or straight.
Compensate for Sloping Ground
If your yard slopes, you’ll need to create stepped trench segments. Start at the lowest point and work uphill, ensuring each section is level across the width of the trench.
Compact the Soil
After excavation, use a hand tamper to compact the bottom of the trench. This prevents settling and provides a more stable base.
Step 2: Lay the Gravel Base
A solid, level gravel base is critical for drainage and block stability.
Add Paver Base or Crushed Stone
- Use crushed limestone or paver base, not pea gravel or loose fill.
- Pour in layers of 2 to 3 inches at a time.
- Compact each layer with a hand tamper before adding the next.
Most projects require about 4 to 6 inches of compacted base gravel. Use a level frequently across and along the trench to ensure consistency.
Step 3: Set the First Course of Blocks
The first course is the most important part of the build. Take your time here—everything above it depends on its accuracy.
Remove the Rear Lip (If Needed)
If you’re using interlocking blocks with a rear lip or flange, remove it from the first-course blocks using a hammer and chisel. This helps the first layer sit completely flat on the base.
Begin Laying the First Block
Start at the lowest point of your wall layout. Place the first block on the gravel base, press it down, and use a level to check front-to-back and side-to-side alignment. Tap gently with a rubber mallet to adjust as needed.
Continue the First Row
Lay each subsequent block tightly against the previous one. Check for level in every direction as you go. If a block is too high or too low, adjust the gravel underneath rather than forcing the block into place.
Step 4: Backfill and Add Drainage After Each Course
As you complete each course of blocks, it’s important to backfill behind the wall for support and water management.
Add Drainage Gravel
Pour drainage gravel directly behind the blocks—at least 6 inches wide. This helps divert water away from the wall and reduces hydrostatic pressure that can cause the wall to fail over time.
Install Landscape Fabric
Lay landscape fabric between the backfill and the native soil. This prevents soil from seeping into the gravel, which would reduce drainage efficiency over time.
Install a Drain Pipe (For Taller Walls)
If your wall is over 24 inches tall or situated on poor-draining soil, install a perforated drain pipe at the base of the backfill layer. This pipe should exit to daylight or connect to a proper drainage system.
Step 5: Lay the Next Courses with a Staggered Pattern
Each new course of blocks should be staggered, similar to bricks, for added strength and visual appeal.
Offset the Seams
Start the second course by cutting a block in half (if needed) so that the joints between blocks do not align with the course below. This helps distribute pressure and reduces structural weak points.
Use a masonry saw with a diamond blade or chisel to cut blocks cleanly. Always wear safety glasses and gloves when cutting block material.
Stack and Align
Place each block so it rests evenly on the course below. Apply slight pressure to ensure the block locks into place if using interlocking units. Continue checking level and alignment with each new row.
Step 6: Apply Construction Adhesive to Top Layers
Once you’ve stacked to your desired wall height—usually no more than 36 inches for DIY builds—use concrete construction adhesive to secure the final rows and capstones.
When to Use Adhesive
- Apply adhesive between the top two courses
- Apply between capstones and the final row
- Use only on clean, dry surfaces for maximum bond strength
Adhesive helps prevent top-layer shifting due to vibration, weather, or minor impacts.
Step 7: Finish the Wall and Fill the Area
The final step is to fill the area behind the wall and complete the visible surface with topsoil, mulch, or decorative landscaping.
Add Topsoil or Mulch
Backfill the remaining space behind the wall with soil if you’re planting, or mulch if you’re building a low-maintenance bed.
Compact in Layers
For soil fill, add it in 6-inch increments and tamp each layer to reduce settling. Slope the surface slightly away from the wall to encourage runoff.
Planting Tips
Choose plants with shallow roots and low water needs near the wall. Avoid large shrubs or trees that could exert pressure on the blocks or interfere with drainage.
Final Checks Before You Clean Up
Walk the full length of the wall to check for:
- Consistent height and straight lines
- Secure caps and aligned rows
- Level tops and proper backfill slope
- No exposed drainage pipe (unless intentionally routed)
A well-built retaining wall should appear solid, balanced, and integrated into the landscape.
Design Ideas, Layout Inspiration, and Landscape Integration
Now that you understand the structural steps behind building a retaining wall, it’s time to think creatively. A retaining wall is not just a functional necessity it can also be an architectural element that enhances the beauty, layout, and usability of your landscape. In this section, we’ll explore smart design ideas and layout variations to make your wall more than just a barrier.
Landscape Design Ideas Using Retaining Walls
Retaining walls offer much more than soil retention. With thoughtful design, they can shape your outdoor space, define specific areas, and even become focal points in your backyard.
Raised Garden Beds
Low retaining walls make excellent raised planting beds. They provide: Better soil and moisture control Easy access for planting and maintenance Beautiful framing for patios, fences, or walkways Perfect for: Herbs, flowers, or shallow-rooted shrubs.
Fire Pit and Patio Walls
Short retaining walls double as seat walls around fire pits or patios. Use them to: Define outdoor rooms Add integrated planters or storage Create cozy zones for social spaces Best for: Hardscape areas where function meets form.
Multi-Tiered Garden Walls
Rather than building one tall wall, use multiple short terraces to follow the slope of your yard. Each tier becomes: A separate planting zone An erosion-resistant layer A design feature with varied textures and height Ideal for: Sloped backyards and hillside gardens.
Framing Walkways and Driveways
Use low walls along paths, steps, or driveways to: Add symmetry and depth Prevent soil runoff in sloped areas Enhance curb appeal Helpful for: Sloped front yards and tiered entrances.
Water Feature Integration
Retaining walls provide structural support around: Garden ponds Cascading waterfalls Rain garden basins Combine with stone steps or plantings to create serene, multi-level focal points. Important: Use proper drainage and waterproofing techniques.
Defining Outdoor Zones
Use walls to separate outdoor rooms like: Grilling stations Dining areas Flower beds or lawn spaces Defined transitions help maximize space and create a polished layout.
Curved Walls, Stairs, and Multi-Level Layouts
Retaining walls aren’t limited to straight lines or right angles. With the right blocks and planning, you can add dimension and flow to your project.
Curved Retaining Walls
Many interlocking block systems are made with tapered edges that allow for curves. Curved walls follow natural contours of your yard and are great for building around trees, patios, or garden beds. When designing a curve: Use a garden hose to lay out the shape Choose blocks specifically designed for radial installations Keep curves gentle tight curves can require cutting or small blocks
Adding Stairs
Stairs can be integrated between walls or within the retaining wall itself, especially in sloped yards. You’ll need wider footings and reinforced structures, especially if the stairway is over three steps. This is a more advanced build but adds strong visual interest and functionality.
Multi-Level and Stepped Walls
If your yard has a significant elevation change, breaking a single wall into multiple tiers reduces soil pressure and improves drainage. Each step-down level can have its own planting theme or functional purpose, such as a seating zone, storage area, or garden bed.
Creative Finishing Touches and Aesthetic Upgrades
Beyond basic block installations, there are plenty of ways to personalize the appearance of your wall.
Capstone Options
Capstones give your wall a clean, finished top and are available in different profiles: Flat capstones: Smooth and modern look Split-face caps: Rugged, textured edges Overhanging caps: Provide a finished ledge Choose a color that contrasts or coordinates with the wall block for maximum effect.
Lighting
Outdoor lighting adds safety and highlights your landscape at night. You can: Install solar cap lights Use hardwired LED strip lighting under caps Add pathway lights behind or beside the wall Lighting enhances curb appeal and extends the functionality of your outdoor space after dark.
Color and Texture Selection
Modern block styles include a wide range of colors, finishes, and textures: Tumbled block: Rustic, weathered finish for a natural look Chiseled-face block: Mimics real stone Smooth contemporary block: Ideal for minimalist patios Split-face or blended tones: Offers depth and character When selecting, consider your home’s siding color, hardscape materials, and surrounding garden style.
Common Retaining Wall Design Mistakes to Avoid
Many homeowners and even DIY-savvy builders run into issues when focusing only on appearance. Here are a few mistakes to avoid when designing your wall:
Ignoring Drainage
Even a beautifully designed wall will fail without proper drainage. Always plan for gravel backfill, filter fabric, and drainage piping for walls over 24 inches.
Overbuilding Without Engineering
Walls over 3–4 feet should not be built without professional advice or structural design. Improperly built tall walls can lean or collapse, especially in wet climates.
Using the Wrong Block Type
Not all blocks are intended for retaining wall applications. Always choose interlocking or specifically manufactured wall block—not pavers, bricks, or decorative stone unless reinforced appropriately.
Skipping the Base Preparation
It’s tempting to start stacking blocks right away, but skipping or rushing the base compaction step will result in settling, shifting, and leaning over time.
Enhancing Long-Term Value
Think beyond today’s project. A well-built retaining wall can serve as a base for future upgrades like:
- Adding a raised patio above the wall
- Expanding garden beds or seating areas
- Installing fencing or railing on top of the wall
- Converting to a multi-tiered system if erosion becomes worse
Designing with flexibility in mind ensures your investment supports your property for decades.
How to Build a Retaining Wall Using Railroad Ties
Railroad ties offer a rugged, weathered look that blends into natural landscapes. Originally used to support train tracks, reclaimed ties are now repurposed for outdoor projects like retaining walls, raised beds, and steps.
Benefits of Using Railroad Ties
- Inexpensive and widely available
- Heavy enough for stability
- Natural wood appearance
- Easily stacked in straight lines
Drawbacks and Warnings
- Often treated with creosote or other chemicals (not recommended near gardens)
- Can rot or attract pests over time
- Heavy and difficult to cut precisely
- Require more anchoring to remain stable
Step-by-Step: Railroad Tie Retaining Wall
- Mark and Measure the Wall Layout
- Use string and stakes to outline the wall location
- Plan for a trench depth similar to a block wall (4–6 inches)
- Excavate and Level the Base
- Dig the trench and tamp the soil flat
- Add 2–3 inches of gravel or crushed stone for drainage
- Lay the First Row of Ties
- Place the first row flat in the trench
- Check for level and adjust with gravel as needed
- Optional: Secure with rebar or spikes driven into the soil
- Add Additional Rows
- Offset seams for strength, like brickwork
- Use 10″ to 18″ landscape spikes or rebar to anchor each row to the one below
- Drill pilot holes before driving spikes to prevent wood splitting
- Backfill After Each Course
- Add gravel and landscape fabric behind the wall
- Backfill with soil or mulch as you build upward
- Finish With a Cap or Top Rail
- Attach a final tie as a cap using screws or spikes
- Add a bench rail or trim board if desired for comfort or style
Important Tip: Only use untreated or specially marked “safe for gardens” wood near edible plants. Avoid using creosote-treated ties for anything that may leach into soil or contact skin.
Troubleshooting Common Retaining Wall Problems
Problem: The Wall is Leaning Forward
Possible Cause: Poor base preparation or saturated backfill
Fix: Disassemble and re-level the base. Improve drainage with more gravel or a drainpipe.
Problem: Water Pools Behind the Wall
Possible Cause: Lack of fabric or incorrect slope
Fix: Add landscape fabric and regrade the soil to slope away. Install a perforated drain pipe if needed.
Problem: Uneven Rows or Gaps
Possible Cause: Inconsistent base height or block irregularities
Fix: Recheck each course with a level and adjust with gravel shims or trimming blocks.
Problem: Soil is Washing Through Gaps
Possible Cause: No landscape fabric between wall and soil
Fix: Carefully remove top layers and insert fabric, then re-stack and backfill properly.
Final Tips Before You Start
Whether you’re building a curved garden bed, a straight patio border, or a multi-level landscape wall, the following tips will help set you up for success.
- Start with a small wall project under 3 feet tall
- Rent tools like a tamper or masonry saw instead of buying
- Use gloves and safety glasses throughout construction
- Check weather forecasts—build only in dry conditions
- Double check utility lines and local building codes
- Take photos of your progress for reference and resale value
- Ask your supplier or contractor about material delivery options
For more complex builds or large slopes, consult with a professional landscaping company to ensure long-term structural integrity.
Sources Used
- Lowe’s. “How to Build a Retaining Wall.” Lowe’s, May 15, 2023. https://www.lowes.com/n/how-to/build-a-retaining-wall.
- Home Depot. “How to Build a Retaining Wall.” The Home Depot. Accessed April 10, 2025. https://www.homedepot.com/c/ah/how-to-build-a-retaining-wall/9ba683603be9fa5395fab901d182a0e.
- Call 811. “Homeowners: Call Before You Dig.” Call811.com. Accessed April 10, 2025. https://call811.com.
- Quikrete. “Paver Base Sand.” Quikrete.com. Accessed April 10, 2025. https://www.quikrete.com/productlines/paverbase.asp.
- Belgard. “Retaining Wall Systems.” Belgard.com. Accessed April 10, 2025. https://www.belgard.com/products/retaining-walls/.
- Better Homes & Gardens. “Best Plants for Retaining Walls.” BHG.com. Accessed April 10, 2025. https://www.bhg.com/gardening/landscaping-projects/structures/retaining-wall-ideas/.
- USDA Natural Resources Conservation Service. “Soil Erosion: Causes and Effects.” USDA NRCS. Accessed April 10, 2025. https://www.nrcs.usda.gov/resources/education/soil-erosion.
International Code Council. International Residential Code for One- and Two-Family Dwellings, 2021 Edition. Country Club Hills, IL: ICC, 2020. https://codes.iccsafe.org.
- Lowe’s. “How to Build a Retaining Wall.” Lowe’s, May 15, 2023. https://www.lowes.com/n/how-to/build-a-retaining-wall.