DIY Cinder Block Retaining Walls With Rebar and Concrete

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As you peruse your domain, you might find it lacking in aesthetic and think a retaining wall will add height and depth to your domicile's outdoor area. Retaining walls can show off your DIY skills and property to its best advantage. Before you dig your first footing or mix your first batch of mortar, there are a few rules to remember when pumping up your outdoor space's visual amenities.

DIY Cinder Block Retaining Walls With Rebar and Concrete
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Basics to Know

Although it is one of the more involved DIY projects, it is also one of the most popular. A well-built cinder block retaining wall can add a sense of a separate, secure space within a wider space, turn a slope into a garden and add living space by holding back a hillside. A cinder block retaining wall requires a bit of heavy lifting and plenty of planning and preparation of the area where you intend to build. Plot out the wall and measure the amount of weight it is expected to hold, if any.


First, approach your footings. Make sure they are solid and a minimum of twice the width of the concrete blocks you've decided to build with. If the wall is load-bearing, meaning it will hold dirt or other heavy substances, the tie rods should be at least 6 inches into the footing before you set the wall. Plop the rebar in every other masonry core for solid support of the finished structure. Lay out your block with a 3/8-inch gap for the mortar joints between each block. A chalk line snapped into place can give you a good reference line if you need it. Mix your mortar and place a 1-inch bed of mortar around the damp footing surface. With the tip of your trowel, push the mortar into the footing so that it creates a V shape. Take your first block and slather the inside end with an even layer of mortar. Place it so that the 3/8-inch gap is filled. Remove excess mortar and continue the process until completed.

DIY Don’ts

Never let a DIY wall tower over more than 3 feet. This can make it less durable to the elements and become a safety issue for the homeowner. If the load that lies behind the retaining wall is within 3 feet of the top the structure, it will start to lean and eventually topple over. Make sure to evaluate how the area drains before you put in the retaining wall. If too much water collects behind the wall, it will saturate the area and compromise the structure. If you live in a frost area, the blocks should be placed well below the frost line so you don't get damage in the future or structural weakness as the weather changes.


Kimberley McGee is an award-winning journalist with 20+ years of experience writing for a variety of clients, including The New York Times, Las Vegas Review-Journal Home section and other national publications. As a professional writer she has researched, interviewed sources and written about home improvement, interior design and related business trends. She earned a B.A. in Journalism from the University of Nevada, Las Vegas. Her full bio and clips can be viewed at

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