Close this search box.
Close this search box.

Boulder Walls

Searching for a boulder wall contractor in Minnesota or great Minneapolis? At Natural Environments Corporation, we pride ourselves on providing excellent quality landscaping services in the Twin Cities Metro area. We’ve been helping our clients bring their landscaping project ideas into reality since 1983. When you’re looking to build a boulder wall, you can count on us to get the job done right. Request a quote today to get started.

What Are Boulder Retaining Walls?

A boulder retaining wall is a retaining wall that’s constructed out of boulders. These can be made out of a variety of different rock types, including fieldstone and more. In a nutshell, they’re designed to hold up soil and to keep soil in place on a slope. Without retaining walls, an area might experience excessive downhill erosion or slope failure, which can lead to a landslide down the line. 

Play Video about Boulder Walls Video

How Are Boulder Walls Installed?

Most boulder retaining walls are constructed with what most people view as large stones or rocks. They are usually two foot diameter stones or larger.

Generally speaking, we have a geo-textile fabric installed behind the wall to isolate the soils from the boulders and to help prevent erosion through the spaces between the boulders. It’s important to have those spaces between the boulders because that’s how we alleviate hydrostatic pressure, which means that’s how we allow water to get through the walls. Otherwise, it gets trapped behind the wall and adds additional pressure to the wall. We will usually add a drainage system as well to further alleviate hydrostatic pressure.

Boulder walls are generally installed with an excavator with a rotating grapple on it. The boulders are picked up with this grapple and they’re spun in circles and placed the way we want them placed. Our experts always place them in a manner that provides the maximum amount of strength and fits the desired aesthetic.

What Are Some Advantages of Boulder Retaining Walls?

Boulder retaining walls have many advantages, including: 

No Reinforcement

Most boulder retaining walls are constructed as a gravity wall. This means that the boulders selected are large enough to be able to support the load that’s being applied to it without needing to add a reinforcement material. It’s an advantage of boulder walls over some other types of products. 

Easily Customizable

Another advantage of boulder retaining walls is that there are many types of boulders available. If the wall needs to be taller or we need to support a heavier load, then we’ll simply size up a stone accordingly. As such, they can be used in a variety of different situations. Boulders also come in a variety of colors and shapes, which allows a boulder wall to fit many different aesthetics.

Minimal Manual Labor 

We’re also able to create the boulder retaining wall without much manual labor, which is another advantage of boulder retaining walls. We try to use machines as much as possible, making the process go faster without compromising excellent results. 


Boulder retaining walls tend to be very long-lasting because the stones we select to build the walls with are generally a long lasting material. They don’t deteriorate, so the lifespan of a retaining wall constructed out of boulders is limited only to the skill of the operator. Overall, they’re one of the longest-lasting walls we’re able to build. 


Additionally, boulder retaining walls can be a very feasible economic choice. They are kind of in the midrange of prices of retaining walls, so that can be a desirable aspect as well.

Natural Aesthetic 

As a final advantage, the aesthetic of boulder walls is more along the lines of something that you might find in nature, which a lot of people find to be a nice addition to a suburban or wooded lot, or maybe a lakeshore property. In this way, a property owner can maintain the natural aesthetic of their property, while still protecting it from erosion or slope failure.

What Happens if Boulder Walls Aren’t Installed Correctly?

Boulder retaining walls require a great deal of expertise during the installation process. This is especially true for boulder retaining walls that are over 4 feet in height, as they will generally require engineering. We always use our licensed structural engineer to design retaining walls that are over 4’ tall. 

Boulder retaining walls are installed in a way that sets them back about 1 foot for every 4 feet in height — we call that the batter of a retaining wall. If you don’t do it properly, the retaining wall will fail. The boulders will wash out and tip over forward. They may also wash out and tip over backward — that’s a little unusual, but on a gravity wall they can actually fall both directions. 

While a properly installed boulder retaining wall will last a lifetime, an improperly installed boulder retaining wall might only last a day. It’s critical to find someone who will install the boulder wall properly.

If you need a boulder wall installed that stands the test of time and protects your property from erosion, you should call the experts at Natural Environments Corporation.

Landscaping Blog

Boulder Walls Gallery

Natural Environments Corporation Frequently Asked Questions

While boulder walls do have some level of natural drainage thanks to the gaps between the stones, we will usually add a drainage system as well. This will depend on the expected hydrostatic pressure that will be applied to the wall when it rains. We determine whether a boulder wall needs a drainage system during the design process.

In terms of general averages, boulder retaining walls typically cost between $40-55 per square foot. The exact amount will depend on the type of stones being used, the size of the wall, and other factors. 

Since retaining walls are designed to support steep slopes, they should be used when there is erosion on a slope to protect a property from a potential future landslide or slope failure. If your property is downhill from a steep slope or there is a noticeable amount of erosion on a slope, you may need a retaining wall. If you’re in doubt, contact our experts, and we will help you determine whether you need one or not. 

The most common reasons for a boulder wall falling have to do with improper installation. For example, if the wall doesn’t have a proper drainage system, the hydrostatic pressure may cause the wall to fall over. If you get an expert to handle your boulder wall, you won’t have to worry about it toppling over. 



Our landscaping services in Minneapolis St. Paul – Twin Cities include landscape design, retaining walls, boulder retaining walls, stone walls, rip rap, shoreline erosion control, patios, driveways, helical piers and more.


Phone: (763) 544-8002
Email: Contact us