What is a Retaining Wall? Purpose, Types, and Benefits

Wondering what a retaining wall is? A retaining wall is a rigid, engineered structure—typically built of concrete, stone, or modular blocks—that holds back soil on a slope, resists lateral earth pressure, and creates level ground while preventing erosion. If you are considering installing one or want to learn more about them, keep reading: this article by Santos Hardscape will walk you through the wall’s purpose, the main types and materials, the benefits for your property, and the warning signs that tell you it’s time to get one.

How Do Retaining Walls Work?

Retaining walls counteract the side-to-side push of soil, a force engineers call lateral earth pressure. The purpose of retaining wall systems is to keep soil in place on different terrains so your yard doesn’t slide, bulge, or erode.

They do this by using their weight (and any built-in reinforcement) to redirect the sideways push of soil down into a solid footing, leaning slightly back to create friction that prevents tipping, channeling water out through drains to relieve hydrostatic pressure, and anchoring deep with footings or geogrid so the wall and surrounding soil act as one stable mass.

Different Types of Retaining Walls (And Their Materials)

Selecting the right wall depends on its design, materials, construction methods, and the conditions on site: soil type, height, load, and budget.

Below is a quick overview of the most popular structures, the best foundation practices, and common wall materials. To compare retaining wall materials specifically, check our blog Best Materials For Retaining Walls: Concrete vs. Natural Stone.

Gravity Retaining Wall

Gravity walls rely on their mass to resist soil pressure. Think thick natural stone boulders or interlocking concrete blocks stacked without mortar. Because weight is the hero, simple gravity walls rarely need deep footings, but they do require space: the base is typically one-half to one-third of the wall’s height.

Gabion Retaining Walls

Gabion walls are wire baskets filled with rocks. They’re quick to assemble, permeable (great for drainage), and have a rustic-industrial vibe because they are made of natural stone. The cages flex slightly, making them perfect for areas with freeze-thaw cycles or minor ground movement.

Cantilever Retaining Wall

A reinforced concrete slab forms an upside-down “T.” The vertical stem holds back soil, while the buried footing (or heel) anchors everything in place. Because cantilever walls convert soil load into downward force on the footing, they’re efficient for medium heights (up to ~20 ft). Accurate steel placement and concrete strength are non-negotiable structural requirements for this wall type.

Segmental Retaining Wall

Segmental walls use dry-stacked concrete blocks with built-in lips or pins that lock rows together. Geogrid layers extend back into the soil, creating a composite mass that resists pressure. These walls are a favorite for residential landscapes because they curve gracefully, match any aesthetic, and install faster than poured concrete.

Do You Need a Retaining Wall? Here’s How to Tell

To determine if you need a retaining wall, walk your property and note the ground conditions. Is your yard losing stability after heavy rain? Does water flow toward the house instead of away? Are there uneven sections of land reducing usable space? These factors signal trouble:

• Soil in place is sliding or cracking.
• Persistent puddles.
• Steep slopes that limit safe foot traffic or mowing.

Key Benefits of Installing a Retaining Wall

A retaining wall is a hardworking sidekick that saves you from muddy messes and turns tricky slopes into beautiful, usable spaces. Here are some of their main benefits:

Prevents Soil Erosion

A wall stabilizes slopes, protects foundations, and prevents you from constantly sweeping gravel off the driveway after every heavy rain by stopping loose rock or soil from washing downhill (regardless of the type of soil).

Improves Drainage

Behind every quality wall is a plan for water drainage. From perforated pipes to gravel backfill, professional installers size drainage needs, pick the right drainage systems, and ensure proper drainage keeps hydrostatic pressure in check. Hence, your yard dries out instead of turning swampy.

Adds Usable Space

Terracing carves out flat zones for lawns, gardens, or a fire-pit hangout, and suddenly, that steep backyard you avoided becomes a multilevel heaven.

Boosts Curb Appeal and Home Value

Texture, color, and subtle lighting transform retaining walls into eye-catching architecture. A thoughtfully designed wall frames plantings, guides guests up pathways, and signals craftsmanship. They are an instant boost to both beauty appeal and resale value.

Creates Levels for Patios, Gardens, or Outdoor Features

A retaining wall turns a steep slope into a series of flat “steps,” giving you ready-made platforms for anything you want to build. One level can host a stone patio, the next a raised vegetable bed, and another an outdoor kitchen or even a small fountain. Retaining walls make your patio a versatile, more usable space.