Gabion Walls

Gabion walls are constructed from wire baskets or cages, which are filled with smaller assorted stones and arranged on the site, either as a quick retaining wall solution or as a free-standing element. Their ease of constructability allows them to be used for a wide range of site modifications, with ready applications across military operations, civil engineering, and more general landscaping use.

Purpose/Uses

The ability of air and water to move freely through the voids of a stone-filled gabion wall enable it to perform a variety of functions in the landscape – the size of the aggregate or material contained within the gabion can be adjusted to suit the purpose of a particular application. As an architectural site feature, gabions can be used to create a sheltered enclosure while allowing for cooling airflow and ventilation. Gabions filled with smaller stones or gravel can be used for erosion/sediment control, and in some cases are used in small streams to create fish screens without creating a dam. In addition to vertical wall applications, gabions can also be used to stabilize embankments or other sloped site features. Designers and engineers have devised myriad applications where the ready constructability and cost-effectiveness of gabion construction are an ideal solution.

With regard to durability, the lifespan of a gabion installation is limited by the wire construction, not the cage’s contents, which are usually stones and therefore highly durable. Galvanized wire is the most common tie material used, but PVC-coated and stainless steel wire also available for added longevity (and cost). Manufacturers of gabion baskets and their components commonly guarantee their products for a lifespan of 50 years.

Construction

Base Preparation

The ground should first be prepared wherever you plan to build your gabion wall. The larger or more substantial the gabion installation, the more important it will be to properly compact your subgrade to be sure the ground will not subside or shift beneath the weight of the stone. It is commonly recommended that 6-12” of earth be excavated out, and an equal amount of crushed stone be added and compacted to be sure of a stable base. It is also usually a good idea to add some type of weed barrier product or landscape fabric on your prepared subgrade to avoid weed growth up into the spaces in the gabion wall. Once vegetation begins to colonize the wall, maintenance can become difficult to perform, so prevention is usually worth the investment of effort.

Wire Basket Assembly

With the base prepared to receive the new wall structure, assembly of the gabion containers can begin. If building custom gabion containers from scratch, a common material is standard concrete-reinforcing  wire mesh, which is available in bulk and relatively inexpensive. Galvanized steel wire should also be acquired for tying the wire mesh panels together.

Panels of the wire mesh should be cut out and arranged to form a box, then tied together by wrapping the edges together with the steel wire. A good video demonstration of this step can be found here.

Finally, the completed baskets should be placed in the desired location (or, at least the first course if there are multiple levels of stacked gabions being installed).

Fill with Stones

The final step will be to fill the gabions with stone. A few ideas for best results (also covered in the above video tutorial):

-Sort through the available stone to find a selection of stones with natural right-angles, or approximately right angles, for use at the corners of the gabions. The more completely the gabion’s volume can be filled, the stronger it will be and the better it will look

-Set up smaller or less visually appealing stones inside the wall, using them for support and to keep the ones that present well to the exterior of the basket. Flat-faced stones are usually best showcased at the exterior faces of the gabions.

-For every 12-15” of stone height added to the gabions, add reinforcing tension wires every 12” for the longitudinal length of the wall between the two long faces of the gabion. This will keep the basket from bulging outward with the weight of the stones enclosed inside

If multiple courses of gabions will be stacked on top of one another to serve as a retaining wall, it is recommended that a batter of at least 1” per foot be used for added stability. This does not apply to free-standing gabion wall construction.

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