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Building Boulder Retaining Walls: A Comprehensive Guide

A boulder retaining wall can be a stunning addition to your landscape, providing both aesthetic and functional benefits. At Utah Boulder Walls, we’re here to guide you through the process of building your own retaining wall using boulders. In this comprehensive guide, we will cover everything you need to know about boulder retaining walls, from choosing the right boulders to a detailed step-by-step guide on construction. Let’s get started!

What is a Boulder Retaining Wall?

A boulder retaining wall is a type of retaining wall constructed using large, natural stones or boulders. Retaining walls are designed to hold back soil and prevent erosion, while also creating level areas in sloped landscapes. Boulder retaining walls are not only effective in their purpose but also make a visually appealing addition to your property.

Advantages of a Boulder Retaining Wall

Some of the key benefits of choosing a boulder retaining wall for your property include:

  • Durability: Boulders are incredibly strong and long-lasting, making them an ideal choice for retaining walls.
  • Low maintenance: Once installed, boulder retaining walls require very little upkeep.
  • Aesthetics: The natural beauty of boulders adds an attractive, rustic touch to your landscape.
  • Environmentally friendly: Using locally sourced boulders for your retaining wall reduces the carbon footprint of the project.

Choosing the Right Boulders

Selecting the appropriate boulders is crucial for the success of your retaining wall. Consider the following factors when choosing boulders:

  • Size and weight: Boulders should be large and heavy enough to provide stability to the wall.
  • Shape: Flat or slightly rounded boulders are easier to stack and create a more stable wall.
  • Color and texture: Choose boulders with a color and texture that complements your landscape.

To get an idea of the variety of boulders available, take a look at our gallery showcasing some of our previous projects.

Equipment, Tools and Materials You’ll Need

Before you begin constructing your boulder retaining wall, gather the necessary equipment, tools and materials:

  • A 15 to 20 Ton Excavator to move rocks **REQUIRED FOR HEAVY BOULDERS**
  • Boulders
  • Crushed gravel or road base
  • Landscape fabric
  • Drainage pipe
  • Leveling Tools (Laser is Best)
  • Work gloves
  • Safety goggles

How to Build a Boulder Retaining Wall: Step-by-Step Guide

Site Preparation

The first step in building your boulder retaining wall is preparing the site. Follow these steps for proper site preparation:

  1. Mark the area: Outline the area where the retaining wall will be built using stakes and string.
  2. Excavate the area: Remove any grass, vegetation, and loose soil from the area, creating a level surface.
  3. Dig a trench: The trench should be at least 6 inches deep and wide enough to accommodate the largest boulders you plan to use.
  4. Add landscape fabric: Lay down landscape fabric at the bottom of the trench to prevent weeds from growing behind the wall.

Setting the Base

A strong base is essential for the stability of your boulder retaining wall. Follow these steps to set the base:

  1. Fill the trench with gravel: Add a layer of crushed gravel or road base to the trench, ensuring it is at least 4 inches deep.
  2. Compact the gravel: Use a hand tamper or plate compactor to compact the gravel, creating a firm base.
  3. Check for level: Use a level to ensure the base is even across the entire trench.

Building the Wall

Now it’s time to build your boulder retaining wall. Here’s how:

  1. Select the base boulders: Choose the largest, flattest boulders for the base of your wall.
  2. Place the base boulders: Starting at one end of the trench, carefully place the base boulders, ensuring they are level and tightly fitted together.
  3. Build the second layer: Continue building the wall by placing boulders on top of the base layer. Offset the seams between boulders in each row, similar to a brick pattern.
  4. Install drainage: Behind the first layer of boulders, place a perforated drainage pipe wrapped in landscape fabric. Fill the area behind the pipe with gravel to promote proper drainage.
  5. Continue building the wall: Keep adding layers of boulders, staggering the seams and ensuring each layer is level. Maintain a slight backward slope (called “batter”) for added stability.

Finishing Touches

After your boulder retaining wall is built, complete the project with these finishing touches:

  1. Fill in gaps: Fill any gaps between boulders with smaller stones or gravel to add stability and prevent soil from washing through.
  2. Backfill the wall: Fill the area behind the wall with soil, tamping it down to create a firm, even surface.
  3. Landscape the area: Plant grass, flowers, or other vegetation around the wall to create a cohesive, attractive landscape.

Tips for a Successful Boulder Retaining Wall Project

Here are some helpful tips to ensure your boulder retaining wall project is a success:

  • Plan carefully: Measure your site accurately and calculate the number of boulders needed before starting.
  • Work safely: Use proper lifting techniques and wear safety gear when handling heavy boulders.
  • Seek professional help if needed: If you’re unsure about any aspect of the project or need assistance, don’t hesitate to contact us at Utah Boulder Walls.


  1. How much does it cost to build a boulder retaining wall? The cost of building a boulder retaining wall varies depending on factors such as the size of the wall, the type of boulders used, and labor costs. Request a quote from Utah Boulder Walls for a personalized estimate.
  2. How long does it take to build a boulder retaining wall? The time it takes to build a boulder retaining wall depends on factors such as the size of the wall, the complexity of the project, and your experience level. Smaller walls may take just a few days, while larger or more complex walls could take weeks.
  3. What kind of boulders should I use for my retaining wall? Choose boulders that are large, heavy, and flat or slightly rounded for the best stability. Also, consider the color and texture of the boulders to ensure they complement your landscape.
  4. Can I build a boulder retaining wall myself? Yes, you can build a boulder retaining wall yourself if you have the necessary tools, materials, and knowledge. However, for larger or more complex projects, it’s recommended to consult with professionals like Utah Boulder Walls to ensure a successful outcome.
  5. How do I maintain my boulder retaining wall? Boulder retaining walls require minimal maintenance. Keep an eye out for any loose boulders or erosion behind the wall, and address these issues promptly if they occur. Also, ensure proper drainage is maintained to prevent water damage.


A well-built boulder retaining wall is not only functional but also adds a beautiful, natural touch to your landscape. By following the steps outlined in this guide and using quality boulders, you can create a durable, low-maintenance retaining wall that will last for years to come. If you have any questions or need assistance with your boulder retaining wall project, don’t hesitate to contact us at Utah Boulder Walls. Ready to get started? Give us a call at 385-417-3854 or request a quote online today!

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