Whether installing retaining walls to make sloping terrain usable, to hold back soil for flower beds or patios, or to help prevent erosion, the design, materials selection, and construction of these vertical structures can be quite an involved process.
But depending on your needs, a traditional retaining wall might not be your only option. Modern segmental retaining walls offer a cost-effective, durable, and simpler alternative to more classic retaining walls. Here are the details:
What Is a Segmental Retaining Wall?
Segmental retaining walls are modular walls made of concrete blocks that interlock together. Their most common application is to hold back soil on sloping terrain.
How do these walls work? Individual blocks can be dry-stacked without the need for mortar to hold them in place. The interlocking mechanisms and the friction between the blocks are sufficient to hold the wall securely.
Segmental retaining walls can be constructed in various sizes: up to 20 feet, and even higher in commercial applications with proper soil reinforcement.
Construction of traditional retaining walls, in comparison, typically involves materials such as poured concrete, stone, or brick. This requires mortar or concrete to bind materials together. Traditional walls also necessitate a solid concrete base or deep footings to maintain stability—particularly in frost-prone areas like our Michigan climate.
The process of installing a traditional retaining wall is labor-intensive and requires specialized expertise to ensure precise placement and alignment. And, due to their rigid structure and lack of flexibility, traditional walls are more prone to cracking from soil movement or temperature fluctuations.
Although a great option in the right situation, the complexity of traditional retaining walls make the segmental route a great option for many.
The Advantages of a Segmental Retaining Wall
Because segmental retaining walls use interlocking, modular concrete blocks that can be dry-stacked without mortar, their construction is simplified. This has the dual benefit of reducing installation time and offering greater long-term flexibility, since the blocks can move slightly without compromising the wall’s integrity.
Additionally, segmental walls typically require only a well-compacted gravel base, further reducing construction complexity and cost. The flexibility of these walls allows for the footing of the retaining wall to be placed above the frost line, making them suitable for various applications in a range of climates.
The manufactured concrete blocks, coupled with the easier installation process, can significantly reduce the overall cost of construction.
Use Cases & Examples
If you’re wondering how segmental retaining walls can improve your yard, here are some ideas to consider:
Terraces in a Sloped Yard: Creating multiple levels in a sloped backyard, providing flat areas for planting, seating, or play spaces
Garden Beds: Constructing raised garden beds that are visually appealing and easy to maintain
Erosion Control: Preventing soil erosion in sloped areas, protecting other landscape features and plantings
Outdoor Living Spaces: Forming the backdrop for outdoor living areas such as patios, decks, or outdoor kitchens
Driveway or Walkway Borders: Defining the edges of driveways or walkways, preventing soil and mulch from spilling over
Pool Surroundings: Creating a stylish and functional border around swimming pools or hot tubs
Separation and Privacy: Building low walls to create a sense of privacy or to define different areas of the yard
Retaining Hillsides: Stabilizing hillsides to prevent landslides or soil movement, particularly in areas prone to heavy rains
Decorative Elements: Adding visual interest with curves and varying heights to the landscape design
Seating Walls: Constructing walls that double as seating areas around fire pits or garden features
Design and Construction Considerations
While the construction process of segmental retaining walls is highly simplified compared to their traditional counterparts, designing and incorporating this feature into your landscape still requires hardscape expertise.
The height of the wall and the strength and thickness of the blocks must be carefully calculated to suit the volume of soil being retained. In some cases, the wall must be installed with more stable backfill soil or gravel and further reinforced by geogrid layers to help retain the soil.
Drainage is also a crucial aspect of any retaining wall design, and segmented retaining walls are no different. Water buildup in the backfill and retained soil can cause hydrostatic pressure to accumulate and potentially stress the retaining wall beyond its limits.
Weep holes are a go-to solution for addressing this issue. These small gaps in the wall allow the water immediately behind the wall to drain out. Additionally, drainage lines with perforated pipes extending back into the backfill can guide water to the drainage holes, providing extra drainage capacity.
Conclusion
Segmental retaining walls provide a modern, efficient solution for both residential and commercial landscaping projects. By understanding the benefits and necessary construction considerations, property owners can create durable, attractive, and functional retaining walls that enhance the landscape while addressing practical needs.
Getting Started with Segmental Retaining Walls
Have more questions about segmental retaining walls? We’d love to discuss the options with you.
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