Retaining walls may look simple — just stack some blocks, pour some concrete, or place some boulders, right? Not quite. A retaining wall is a structural system designed to hold back thousands of pounds of soil, water pressure, and shifting earth. When they’re not built correctly, they fail. And when retaining walls fail, the damage can be expensive.

At Vicente Outdoor Living, we see many retaining walls collapse because the original builder didn’t understand the engineering behind them. If you’re thinking about building a wall or repairing an existing one, here are the biggest mistakes homeowners make — and how to avoid them.

1. No Drainage System Behind the Wall

This is the most common (and most destructive) mistake.

Without proper drainage, walls can:

• bow forward
• crack
• lean
• collapse
• suffer water pressure buildup

A retaining wall must have drainage rock and a perforated drain pipe behind it. Water pressure is often stronger than the soil itself — and it destroys walls from the inside out.

2. Using the Wrong Material for the Wall’s Purpose

Not every wall block or material is designed to hold back soil.

Common DIY material mistakes include:

• stacking decorative blocks without reinforcement
• using railroad ties that rot over time
• placing loose rocks with no support
• building tall walls with small blocks
• using untreated lumber

Choosing the wrong material is one of the fastest paths to failure.

3. No Footing or Poor Base Preparation

A retaining wall is only as strong as the base it sits on.

Proper base preparation requires:

• digging a trench
• adding compacted gravel
• leveling the base
• burying part of the first course

When the base isn’t prepared correctly, the wall shifts, leans, and eventually collapses.

4. Building the Wall Too Tall Without Engineering Support

Every retaining wall has a safe height limit depending on the material and design.

DIY builders often:

• exceed safe height limits
• don’t use geogrid reinforcement
• underestimate soil pressure

Once a wall gets above 3–4 feet, it often requires deeper engineering and reinforcement.

5. Not Using Geogrid Reinforcement

Geogrid is like the “seatbelt” of a retaining wall — it ties the soil and wall together.

Without geogrid:

• soil pushes forward
• the top of the wall leans
• long walls fail in sections
• water pressure overwhelms the structure

Reinforcement is essential for stability.

6. Poor Water Management Around the Wall

Even if the wall has drainage, surrounding water sources can still cause issues.

Problems include:

• downspouts dumping water onto the wall
• runoff from slopes
• poor yard grading
• irrigation overspray

Walls need strategic water planning to survive long-term.

7. Using Soil as Backfill Instead of Gravel

Soil absorbs water and becomes heavy, which increases pressure behind the wall.

Proper backfill materials include:

• crushed gravel
• clean stone
• mixed aggregate

These materials drain faster and reduce pressure.

8. Building a Wall on a Slope Without Stepped Footings

If the wall sits on a slope, the footings must be stepped to match the grade.

Skipping stepped footings causes:

• sliding
• uneven settling
• leaning
• wall separation

The wall must work with the slope — not against it.

9. Assuming a Retaining Wall Is Just a Decorative Border

Many homeowners underestimate the engineering behind a retaining wall.

But retaining walls must handle:

• soil weight
• water pressure
• ground shift
• freeze-thaw cycles
• erosion

Treating a structural wall like a decorative flower-bed border almost always ends badly.

10. Not Considering Long-Term Soil Movement

Ground shifts naturally over time, especially in Texas clay soils.

Walls must accommodate:

• expansion and contraction
• soil settling
• seasonal movement

Without flexibility or reinforcement, walls begin to crack or bulge.

11. No Professional Assessment for Failing Walls

Some homeowners attempt DIY fixes to walls that are already failing.

Common failed repair attempts include:

• adding more blocks to the front
• applying concrete patches
• inserting wood braces
• draining water incorrectly

Improper repairs often make the problem worse.

12. Skipping Professional Installation Entirely

Building a retaining wall involves:

• structural engineering
• drainage systems
• compacting and grading
• reinforcement planning
• proper base construction
• material knowledge
• percussion compaction

A poorly built wall may last one season — but a professionally built wall can last decades.

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