A retaining wall is one of the best ways to prevent soil erosion and add structure to your yard—without breaking the bank. The most budget-friendly options include landscape timbers ($12–$15 per square foot) and free natural stone if you have access to it.
Concrete blocks and interlocking blocks cost more but provide better durability.
If you’re tackling this as a DIY project, landscape timbers are the easiest to install. However, for walls taller than 4 feet, reinforcement with rebar or a concrete footing is essential to prevent failure.
In this guide, we’ll break down the cheapest retaining wall materials, compare their pros and cons, and offer expert tips for building a sturdy, long-lasting wall.
What Is a Retaining Wall?
A retaining wall is a landscaping structure designed to hold back soil and prevent erosion. These walls are commonly seen along highways, where they keep hillsides from collapsing onto the road. In residential settings, retaining walls support driveways, patios, and garden beds, especially in sloped yards. When combined with proper drainage and vegetation, they provide an effective erosion control system.
What Is the Easiest Retaining Wall to Build?
For DIYers, the simplest retaining wall to install is one made from landscape timbers. These are often mistaken for standard pressure-treated 4x4s, but they are actually lower-grade lumber, designed for strength rather than appearance.
Landscape timbers have rounded edges, allowing them to stack neatly like logs. Long, corrosion-resistant spikes secure the timbers in place, preventing movement.
However, because landscape timbers are only 3” x 4” thick, they aren’t strong enough for walls over 4 feet tall.
Can I Build a Retaining Wall Myself?
Yes! Many homeowners successfully build their own retaining walls, especially small ones. The easiest DIY option is landscape timbers, which require basic tools like a saw and hammer.
For those with masonry experience, concrete blocks or interlocking cement blocks are also viable DIY options. However, these materials require more labor and, in some cases, additional reinforcements like rebar or concrete footings.
What Is the Cheapest Way to Build a Retaining Wall?
Here’s a breakdown of the most affordable retaining wall materials, ranked from least to most expensive.
Landscaping Timbers
Landscape timber walls are one of the most budget-friendly and easiest retaining walls to build. All you need are the timbers and large spikes to secure them in place.
Cost: About $12–$15 per square foot
Natural Stones
If you have access to free slate, river rock, or fieldstone, you can build a retaining wall at little to no cost. Mortar is typically needed to hold stones together, and for taller walls, additional support like rebar may be necessary.
Cost: $0–$30 per square foot
Concrete Blocks
Concrete blocks are one of the most common retaining wall materials due to their affordability and strength. When reinforced with concrete and rebar, these walls can support significant weight. However, they require a concrete footing, which adds to the overall cost and labor.
Cost: About $20–$30 per square foot
Interlocking Concrete Blocks
Interlocking blocks lock together using a lip along their base, forming a secure structure. Because they don’t require mortar, installation is easier. However, site preparation, including leveling the ground and laying a sand base, is essential.
Cost: About $20–$25 per square foot
Poured Concrete
Pouring a solid concrete retaining wall creates the most durable structure but requires significant excavation and labor. More than 50% of the cost comes from labor, making it expensive for larger walls.
Cost: About $25–$40 per square foot
Railroad Ties
Railroad ties are treated with creosote, a chemical that makes them resistant to rot and insects. However, creosote can cause skin irritation, so proper handling (gloves, protective clothing) is essential.
To install, railroad ties are stacked and secured with large spikes or rebar, with the bottom tie partially buried for stability. Walls taller than 4 feet should be reinforced with additional support.
Cost: About $25–$30 per square foot
Build the Wall For Strength
While aesthetics matter, strength is the most important factor in a retaining wall’s design. Professional builders prioritize structural integrity before appearance.
To ensure your wall stands the test of time:
- Use proper materials for your desired height.
- Reinforce walls over 4 feet with concrete footings or rebar.
- Ensure proper drainage to prevent pressure buildup behind the wall.
If you’re unsure how to design a retaining wall that will last, consulting a structural engineer is a wise investment. A properly built wall will effectively control erosion and enhance your landscape for years to come.
