Building a retaining wall is a highly rewarding DIY project that can dramatically transform your landscape by managing slopes, preventing soil erosion, and creating usable flat spaces. Although it requires effort and careful planning, understanding the essential steps and techniques can make the process manageable and ensure a sturdy, long-lasting wall. This guide walks you through every critical stage—from design to finishing touches—so you can confidently build your own retaining wall.

1. Designing and Planning Your Retaining Wall

Before digging or laying the first block, take time to carefully plan the wall’s design:

Determine the Maximum Height
The tallest point of your wall will dictate key factors like block size, base thickness, and drainage requirements. Smaller walls (around 3 feet tall) are easier to manage, but taller walls need additional engineering considerations.

Choose Your Blocks
Selecting the right retaining wall blocks affects both stability and aesthetic. Blocks with a lip are ideal because they interlock better and provide added strength. Most local suppliers or rock yards can recommend appropriate block types and gravel for drainage.

Consider Where the Dirt Will Go
Retaining walls push back earth, which you’ll need to place somewhere. Decide if dirt will be stacked behind the wall or removed, and calculate if additional soil is needed to fill the space atop the wall.

Check Local Codes and Utilities
Always verify that your wall complies with local building regulations. Also, ensure no underground utilities are in your construction path by contacting local utility companies.

2. Excavation: Digging the Trench

Once your design is finalized:

Mark Your Wall’s Location
Outline the wall’s path and dig a trench about 9 inches deeper than your ground level to properly seat the base and the first block layer.

Trench Width and Leveling
Dig the trench approximately 20 inches wide to allow room for gravel backfill and to maneuver blocks. It’s essential that the trench bottom is perfectly level to prevent shifting.

Handling Difficult Soil
If your soil is rocky, tools like a pickaxe or digging spike might be necessary. Take your time—the excavation phase often takes the most effort.

3. Building a Solid Foundation with Gravel Base

The foundation prevents your wall from shifting or collapsing under pressure:

Lay a 6-inch Layer of Packed Gravel
Use type 2 gravel—rough rock about ¾-inch in size—which provides excellent drainage and stability. Add gravel in 2-inch layers, raking each layer evenly.

Tamp Thoroughly
Compress each gravel layer with a hand tamper. If the gravel is dry, mist it with water to help pack it down more firmly.

Level Once More Before Blocks
Before placing blocks, double-check the gravel base is level. This foundation supports the entire weight of your wall.

4. Setting the First Row of Blocks

This is the most critical and labor-intensive step:

Start From One End
Lay blocks one at a time, ensuring each is perfectly level front-to-back and side-to-side. Use a level constantly to check your work.

Make Adjustments with Sand
If a block is uneven, lift it, add or remove sand underneath to level it, and then retamp. Adjusting the sand is easier than regrading the gravel.

Bury Half of the First Block
About half of the bottom block’s height should be below ground level to provide stability.

5. Building Up the Wall

Once the first layer is set:

Stack Additional Rows
Place the next row of blocks on top of the previous one, staggering the seams for added strength.

Do Not Angle Blocks on Slopes
If building the wall up a hill, step it up in levels rather than angling the blocks. Each block must rest perfectly level for structural integrity.

Backfill and Tamp Behind Each Layer
Fill the void behind the blocks with ¾-inch gravel, then pack it firmly with a tamper to prevent settling and pressure buildup.

Add Dirt in Front
Also backfill and tamp dirt in front of the blocks to hold them steadily as you build.

6. Installing Drainage

Proper drainage is crucial to prevent hydrostatic pressure that can push the wall over:

Use Gravel as Drainage Layer
Gravel behind the wall allows water to flow down and relieve pressure.

Consider a Drain Pipe for Taller Walls
For walls over a certain height or heavy loads, a perforated drain pipe placed at the base can direct water away effectively. Consult local guidelines and a professional, if necessary.

7. Finishing Touches

Top Layer Stability
Glue the top blocks with construction adhesive to prevent them from shifting or being removed.

Final Soil Layer
Cover gravel with topsoil — avoid tamping the topsoil so plants can grow, if desired.

Cutting Blocks
To fit corners or curves, score blocks using a mason’s chisel and mini sledgehammer by tapping around a drawn line until the block snaps cleanly. An angle grinder with a diamond blade is an alternative for many cuts.

8. Recommended Tools

Equip yourself with these essential tools for an efficient workflow:

Rake, spade, flat-nosed shovel
Pickaxe or digging spike for rocky soils
Hand tamper for gravel packing
Various levels (4-foot, 2-foot, torpedo level)
Mason’s chisel and mini sledgehammer for cutting blocks
Rubber mallet and caulking gun for adhesives
Optional: stakes, string, and line level for marking and leveling

Final Thoughts

Building a retaining wall is undeniably labor-intensive, especially if working solo. A 50-foot wall about 3 feet tall, for instance, can take weeks of part-time labor, but the results are well worth it—improved landscape usability, effective soil management, and a visually appealing yard upgrade.

By following this step-by-step approach, ensuring your foundation is strong, leveling each block carefully, and installing proper drainage, you’ll construct a durable retaining wall that stands the test of time.

Whether you’re a DIY enthusiast or a homeowner looking to enhance your outdoor space, these tips and techniques will help you master retaining wall construction successfully. Happy building!