What are Gravity Retaining Wall Extenders?

Have you seen MagnumStone’s big block gravity retaining wall design before? It it’s your first time, don’t worry; it’s natural to be inquisitive about the system’s distinctly unique features. We’ll touch on MagnumStone’s hollow core blocks and strikingly natural rocky facings in another blog. Here, we’ll focus on the one-of-a-kind gravity retaining wall extenders and their impactful performance, which is universally applauded by retaining wall designers, installers and property owners.

It’s been well-documented that with dramatic increases in development and infrastructure, the value of land is soaring. Gravity extenders make the most of available space. Whether your upcoming projects are new commercial developments, government infrastructure or backyard renovations, gravity extenders are a worthwhile investment for project designs.

What are MagnumStone Gravity Retaining Wall Extenders?

Glad you asked, let’s dive in. Gravity retaining wall extenders are aptly named and only used for MagnumStone’s gravity retaining wall designs. The tongue-and-groove system serves as an addition to the back of MagnumStone’s hollow core standard blocks – and other extenders. Thanks to extender units, the retaining wall gains extra mass, with the versatility of 2 ft. (0.67 m.). and 4 ft. (1.2 m.). increments. This enhances a project’s functionality and design options, with a proven track record of success.

The option to use short and long gravity extenders is a win-win for designers, installers and property owners. Minimizing excavation area also provides cost savings by lessening labour hours throughout the installation. This reduces land disturbance, which makes landowners (and Mother Nature) happy, plus gravity extenders significantly cut excavation time and equipment costs. The built-in lifting hooks make gravity extenders easy to move and install with small equipment. With two different size extenders to choose from, designers can get closer to property lines to maximize available land.

How do Gravity Extenders Minimize Excavation Area?

A key advantage of MagnumStone’s short and long extenders is the impact on base-to-height ratios regarding excavation area. Depending on the height of each retaining wall design, extenders are required to add mass. With MagnumStone’s extenders, the base-to-height ratio can be as low as 40%. This means that the excavation area’s depth may only be 40% of the height of the retaining wall’s height. Comparatively, geogrid retaining walls typically require a 70% base-to-height ratio for excavation area.

To put this in perspective, let’s consider a 20 ft. (6.0 m.) tall retaining wall. Using MagnumStone’s gravity retaining wall extenders, this wall could have as low as 8 ft. (2.4 m.) excavation depth (under perfect conditions). Using a geogrid application, that same retaining wall’s excavation depth would be 14 ft. (4.3 m.). Imagine the possibilities for your property or development if you had an extra 6 ft. (1.8 m.) of space to work with!

3D diagrams above show the excavation area required for geogrid retaining walls compared to that of gravity retaining walls using MagnumStone gravity extenders.

How to Design Projects with Gravity Extenders

Why would gravity retaining walls need extenders? These extender units help designers plan taller gravity retaining walls thanks to the extenders anchored behind the wall. From a design aspect, this provides a simple solution with far more flexibility to build taller walls with more customized features. The depth of excavation can be designed in 2 ft. (0.67m) increments, allowing for smaller design depth increments. Through these versatile lengths, designers are not forced to use pre-determined lengths of depth blocks. This has often resulted in designers using depth blocks that are unnecessarily large for the scope of their project. Design your gravity retaining wall with extenders today with our free, comprehensive MagnumStone Retaining Wall Design & Analysis Software.

Gravity Extenders Make Outside Corners Simpler  

The flexibility of extenders is advantageous for complex retaining walls that contain tight corners with limited space and varying loads. The flexibility of the short and long extenders allows users to overlap the extenders over top of each other. Since outside corners are a critical feature of retaining walls which require extra strength and well thought-out design, short and long extenders are a true game-changer.

By alternating the extender lengths throughout each layer, outside corners gain extra reinforcement. The strategic combination of short and long extenders helps designers by fitting areas that traditional 4 ft. extenders cannot. The 2 ft. (0.67 m.) & 4 ft. (1.2 m.) gravity extenders can add an extra measure of strength and protection to any project’s outside corner features.

How Do You Install Short & Long Extenders?

MagnumStone’s retaining wall system was built by contractors, for contractors, therefore installation of gravity extenders is simple and efficient. Considering their solid stature, gravity extenders are still light blocks, making them easy and cost-efficient to ship and install. The extenders have a simple, efficient tongue and groove which can be slotted together for a strong, stabilized fit.

The gravity extenders can be installed using less heavy equipment, as small excavators and backhoe loaders are capable of lifting the units. Only two people are required to install gravity extenders. Those are the equipment operator and another person to hook and unhook the units, then guide them into place.

With MagnumStone’s globally-renowned quick installation process, contractors can save big on labor, reallocating budget and resources to other critical projects. Check out our free step-by-step installation guides here.

Short and Long Gravity Extender Production & Inventory

Short and long extenders are manufactured and stocked separately from the standard blocks. This allows for simple design changes on paper and also on site. If more depth is required, a 2 ft. extender can simply be added to the back of the design and easily installed. From a production standpoint, this means taking blocks directly from sitting inventory rather than changing production for certain depth blocks.

Learn More About Gravity Extenders

Connect with your nearest MagnumStone expert by finding your local MagnumStone dealer or supplier. Our free online resources include the MagnumStone Retaining Wall Design & Analysis Software, Instant Estimator and step-by-step Installation Guides.

These tools can provide accurate preliminary designs, material estimates and installation techniques that include MagnumStone’s outstanding gravity retaining wall extenders. To learn more about our full MagnumStone system, take our free virtual 1-hour MagnumStone Education 101 retaining wall course online today.


Photos: York Building Products, Cirtex, Masters Concrete Products, BM Valla and Midwest Block & Brick.


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