Retaining Wall Basics

Retaining walls aren’t just visual elements. They're structural systems built to resist pressure, manage water, and create usable space on sloped ground. Done correctly, they last for decades. Done poorly, they crack, lean, or collapse—and cost a fortune to fix.

Here’s what goes into a properly built retaining wall in Central Texas:

1. Start With a Proper Footing

The base of the wall—called a footing—is everything.

You’ve got two solid options:

• Dry Stack Footing: Excavate a trench and line it with geotextile fabric, then add angular clean gravel. This provides a stable, level, and draining base for natural stone or manufactured block.

• Concrete Footing: For mortared walls, pour a reinforced concrete footing at the correct depth and width. This is critical when dealing with taller walls or high loads.

The key is starting below grade, on undisturbed soil or rock, and creating a flat, stable, compacted base.

2. Backfill the Right Way

Behind every wall, the backfill controls both pressure and drainage.

The correct method:

• Lay geotextile fabric first, directly on the native soil or bedrock.

• Then place clean, angular gravel or crushed stone on top.

• The fabric and gravel create a free-draining layer that keeps soil out of the gravel and prevents clogging.

• This zone should extend at least 12 inches back from the wall.

• Warning: Backfilling with native clay or mixed soil is asking for trouble.

3. Plan for Water Control

Water is the most common reason walls fail. If it can’t escape, it builds up pressure behind the wall.

• Dry-stack systems (using manufactured block or cut natural stone) allow water to drain naturally through gaps.

• Mortared systems (brick, block, or stone) must include weep holes—typically 2-inch drain ports every 6 to 10 feet—at the base of the wall.

• All systems should include a perforated drain pipe (with filter sock), set at the base of the wall and sloped to daylight. Without that, hydrostatic pressure builds up and blows out the wall over time.

4. Use the Right Materials

Choose what fits your site, aesthetic, and budget—but know the strengths of each.

• Manufactured block systems are engineered for consistency and are often easier to build for taller walls.

• Natural stone can be dry-stacked if it’s cut properly or laid in mortar if footed correctly.

• Mortared block or brick offers a clean look but demands precision and robust drainage design.

5. Reinforce When Needed

If your wall is taller than 4 feet, or has vehicles, structures, or slopes above, it may require:

• Geogrid reinforcement: mesh layers tied back into the soil to increase stability.

• Engineering: A structural engineer may be required by code or common sense, depending on the load and conditions.

6. Consider Local Soil and Load Conditions

Central Texas soil ranges from hard limestone to expansive clay. The wrong footing or poor drainage in these conditions will cause heaving, leaning, or collapse.

Heavy water runoff, tree roots, and adjacent construction should all be factored into the design.

7. Tie It All Together With Smart Landscaping

• Avoid overwatering near the top edge—this increases pressure and washouts.

• Use drip systems instead of overhead spray.

• Choose plants with non-invasive roots, and position them strategically to avoid future maintenance issues.

Bottom line:

A retaining wall is not a weekend DIY project. It’s a structural element that requires proper planning and execution. When it’s built right, it protects your property, prevents damage, and improves aesthetics and functionality.

Disclaimer: This article is intended for general informational purposes only and does not constitute engineering, legal, or construction advice. Site conditions vary, and retaining wall construction may require permits, inspections, or professional engineering depending on location and scope. Always consult with a licensed professional before beginning any structural landscape work.