How To Build A Wall On A Slope

Retaining walls add value to residential and commercial properties because they provide reliable property boundary markers, prevent soil erosion, and allow you to make better use of your landscaping space.

A common use for retaining walls today is to create terraced areas that become suitable for planting. If your property is on a slope, you’ll build flatter spots that are more usable for different needs.

Boulders, pavers, bricks, concrete blocks, and even wood can help you to build an effective retaining wall on a slope. If you plan to DIY this project, here are the steps to take to have a successful experience.
Steps to Follow When Building a Retaining Wall on a Slope

When you start building a retaining wall on a slope, the first project is to create the various step-ups you’ll need for the property. That process begins at the base, where the lowest wall elevation will get constructed.

Although every property has unique features to consider, you’ll typically dig a base trench that is 24 inches wide. You’ll determine the depth by allowing for six inches plus an additional inch for every one foot of wall height for the number of buried blocks or materials needed.

If your wall is under four feet high, you can dig the base trench to be 18 inches wide and four inches deep, along with whatever space is necessary for buried blocks.

The trench must also extend into the hill far enough to bury a whole block. If you have a slope below the start of the wall, an engineer is usually needed to complete the initial steps.

Step #1: Get the Trench Compact and Level

After you have the base trench completed, you’ll need to make that area compact and level. A plate compactor is usually required for this part of the job. It takes a minimum of two passes to achieve an acceptable result, and it sometimes needs 4-6 passes to build the proper foundation.

Once you have this step completed, you can place the drainpipe for the retaining wall at the lowest point at the back of the trench.

Step #2: Install the Wall Rock

You need to place at least six inches of wall rock along the base trench. Once you have it in place and level, you’ll need to make at least two more passes with the plate compactor to ensure you have the stability necessary for your project.

Step #3: Excavate the Second Level

Once you have the trench in place, you’re ready to create the second level of your retaining wall getting built on a slope. You’ll want to make sure there is enough room for the buried rock and base material for this area. After you get everything in place, you’ll need to compact the area, making sure it is level.

Step #4: Place the Base Course of Blocks

After completing the trench and the step-up area, you can place the base course of blocks on the base material. Always check for level with each addition to ensure your work is stable and supportive.

If you use concrete blocks, it helps to fill the hollow cores for added strength. The blocks and the base of your next step-up level should be equal once you’ve completed the building work.

Step #5: Compact the Wall Rock Behind the Blocks

Once you have the blocks in place, you’ll need to run the plate compactor along the wall rock to ensure the slope supports are in place. You’ll continue that work to the top of the grade. Please remember that every block at each step-up level must be buried entirely to ensure the correct base depth. If you forget that step, erosion can eventually lead to wall failure.

Step #6: Fill in the Step Up Areas

After you build the retaining wall, you’ll likely have gaps to fill with soil or other landscaping materials because of the slope. The goal is to create a flat, level result that meets your needs. You don’t need to compact these materials, especially if they’ll be used for flowerbeds or other features.

Concluding Thoughts

These are the steps you need to build a retaining wall in your yard. This method can be used on flat ground or a slope. Keep those key points in mind when building on a slope or hill. Remember that your stepped trench and foundation layers are the most important and difficult steps in building. No matter the difficulty, when you have a finished retaining wall as part of your landscape, you will feel that it was worth it. We hope you found this article helpful when it comes to building a wall of your own. 

If you have any questions about building a retaining wall on a slope for your next residential or commercial landscaping project, contact us

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