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Three Retaining Wall Construction Mistakes To Avoid

by Dan Mckinney

In many landscapes, retaining walls are a necessity if you want to level or terrace uneven terrain. Fortunately, these walls can be just as ornamental as they are structural. The key is to make sure the wall is properly installed so it doesn't bow out or collapse in the future. Avoiding the following mistakes is key to achieving this.

#1: Not installing drains

A wall may appear to help level the slope it supports, but water will still drain downward through the slope and towards the base of the retaining wall. The wall can then impede the drainage, which leads to concentrated water accumulation behind the wall that can cause it to bow or even collapse. The key to avoiding this issue is to construct a wall with proper drainage. Most installers use one of two methods for drainage. If there is lawn or garden beds in front of the wall at the lower end, then exterior drains are often installed in the base of the wall so the moisture can trickle into the landscaping. If the wall borders a sidewalk or drive, then a drain pipe should be installed behind the wall to route water to a safe place.

#2: Skipping the footing

Every retaining wall, no matter how short, should have the proper footing. The type of footing your wall needs depends on your soil type, the weight it supports, and the materials it is made out of, but there are some basic guidelines. Generally, the footing should extend below the average frost line in your area. In other words, if the top 6 inches of ground tends to freeze each winter, the footing should extend deeper than 6 inches so it isn't prone to frost heave. The second guideline is that the footing should be wider than the base of the wall so that the weight of the wall is distributed over a wider area. Footings are usually made of gravel, sand, or concrete, although other materials are sometimes used.

#3: Ignoring reinforcement concerns

Every wall is different in terms of the amount of weight and pressure it is subjected to. The construction method and materials also come into play when determining how to reinforce the wall. Wall made of interlocking or dry-fitted stone with no mortar, for example, should only be used to support minimal weight or pressure, while mortared walls are better for areas subjected to more weight stress. Poured concrete also works well in highly supportive retaining walls, but it can crack. In this case, reinforcing bars, or rebar, must be used to build a framework that the concrete is poured around to provide the extra support. Make sure the wall you choose is designed with proper reinforcement.

For more help, talk to a retaining wall contractor at a company like New Horizon Landscapes & Design in your area.