How to Build a Retaining Wall on a Steep Slope

Retaining walls add all the functions of the outdoor living space and increase the attraction in your landscape. It is the most natural way to control soil erosion, provide usable space for your home, reduce steep slopes or problems related to slopes add more unique planting bed designs, and create the focal points for your landscape garden. Building a retaining wall might seem simple to install and be reasonably priced with high maintenance, as well as a variety of colors, textures, and ideas for almost all homeowners to choose to make use of their outdoor living space.

Retaining walls provide protection against the steep slopes, especially with houses on the high hillside. If there is a slope in your residential area, it can cause some problems with the drainage system, even floods. A precise-retaining-wall installation help reduce slopes significantly and maintain the garden yard, as well as your property perfectly. On the other hand, miscalculating the building plans will lead to a weak wall or even the collapse of the existing architecture.

When planning to build retaining wall ideas, you should find out what to do before going to any physical work. Whether you want to do it yourself or hire professional constructors, in some steps of installation, a retaining wall will require professional engineering to keep its shape. Retaining walls taller than 4 feet should be constructed by a prof. Although you can still DIY, it’s better to consider finding a constructor and an engineer for grading or drainage to avoid unwanted damage.

Follow this article to take these steps as a guideline on how to install a retaining wall on a slope by yourself.

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A thorough retaining wall design will enhance the function of your house and add elegant value to your property. Retaining walls combined with each landscaping detail into a sloped yard provide you an opportunity to create living spaces and welcome guests come to your yard garden.

Stabilize a Slope


The most obvious use of a retaining wall is to reduce steep slopes. You can use stacked bluestone as a simple way to combine both modern and vintage styles for your walls with the beige color behind them. The creativity for your landscape should run along with its function. Don’t let the slopes hinder you from designing your property. Building a retaining wall will give you the best answer for issues of soil erosion and drainage on a slope.

Provide Usable Space for Sloped Area

Most homeowners think that sloped areas are unusable, however, the retaining walls will carve out usable spaces. In many landscaping designs, you totally can use a retaining wall to provide adequate spaces for the entire yard and house with a walkway, a pool, sitting area, firepit area, entertaining area, etc. which will have a large impact on the slope of your backyard.

retaining wall with entertaining area

An experienced contractor can transform the curve land into the driveway or walkway with a planting bed along the hillside to create the patio or provide enough space for the outdoor living area, playing area, garden yard, etc. in the areas which were once a high hillside. Retaining walls make these areas smoother and provide flat spaces for outdoor landscaping with stunning function styles.

Reducing Soil Erosion

The most important function of retaining walls is to battle gravity and keep the soil, as well as water from moving downwards the hill. Because of that, when you consider providing safety for your house and garden, landscaping a retaining wall will help you against soil erosion. It holds back to earth around the foundation and eliminates the threat of sliding soil.


Before You Start Building Retaining Walls

The first thing you should do is to check the local codes for requirements and check whether there are any underground utility lines before going to any steps of building the retaining walls. In case you’d like to hire a landscaper instead of DIY, make sure this address also has the permit from your local utility companies.

checking the water runoff and drainage

Keep checking the water runoff and drainage in mind during this project and ensure that the water systems from your house will not be puddled and reduce the endurance of stairs. Call 811 – DigSafe to ask about the local utility companies before you plan to dig anything up. Then determine whether there are any underground lines and mark the exact locations to avoid them during the process.


To build a retaining wall DIY, make sure you have these right tools. The process will be easier for you and save your time with them:

  • Round point shovel: This is useful for moving plants, excavating, and establishing a foundation.

  • Square blade shovel: It’s ideal for laying down materials like gravel or sand and grading the region.

  • Tamper: Helpful to tamp down the area.

  • 4 ft. level: Check to see if the work area and the rows of retaining walls are levels.

  • Drilling Hammers: To drive stakes into the ground, a mallet and a 5-pound maul may be useful.

  • Adhesive and caulking gun: If you wish to attach finishing caps or add steps, these supplementary materials will come in handy.

  • Block chisel

  • Tape measure

  • Circular saw

  • Transit level

In addition, you should prepare safety glasses and a dust mask to protect yourself from physical harm.


There are 4 common types of building materials: poured concrete, interlocking blocks, stacked stone, and brick/block. You should plan a list of which materials you need to buy ahead of time you go shopping. This will help you save a significant amount of money and time. This list will include:

  • Retaining wall blocks: there is a catalog of each manufacturer that you can opt for your different options of style, color, size, and pattern. And remember when you use the block as a building material, you should keep the lower block inclined slightly to avoid water collecting on itself.

  • Paver Base

  • Concrete stones

  • Concrete adhesive

  • Concrete pavers

  • Sand and gravel

  • Landscape fabric

When you prepare all the tools and materials along with you, the next part will show you how to build a retaining wall DIY step by step.

Retaining wall blocks


Use the tape measure to determine the length of your wall. Then divide this number by the length of each block you plan to use for your project. In this way, you’ll probably know how many blocks you need to use per row. And to determine how many rows are in your own project, divide the length of your wall by the height of the block.

measure the length of wall


Only when your retaining wall has a strong foundation system, your project will maintain its longevity. Dig the trench where you plan to install the wall with at least 4 inches in depth and 24 inches in width. For the sloped area, you’ll want to level the trench to have space for keeping the stone blocks. For a stacked-block retaining wall, provide an area of at least 4 inches for adding the crushed rock behind the wall to keep it settle.

dig the trench

However, this is just a recommendation. The exact depth of the trench should equal an eighth of the visible retaining wall plus three inches of crushed rock.


Use a hand tamper to tamp down the paver base which you added into the trench. Tamp it until it’s below the tops of the stakes about 1 inch. Then, use a garden hose and spray the paver base down to compact it into the soil.

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Build a retaining wall on a Slope Posted


It’s time to install a retaining wall with the first layer. The first course of blocks must be installed on a flat sand base, if not, the rest of your retaining wall will be unlevel too and unattractive.

Level the first row

Before going to place the blocks, use the 4 ft. level to ensure the gravel sand below the first course is even. Use a hammer and block chisel to cut blocks and check the levelness from front to back.


For the first course of block installation, you will use a straight row with a taut string line. Set the first block in the lowest location of the trench and always check for levelness. Then, continue to lay the next blocks which will be even with the first one.

fill the first course


When finished installing the first row, to keep the wall in place, pack native soil to grade level on both sides of this course.

masonry blade

Use a masonry blade to cut blocks for the second row of a retaining wall and then put them into the position against the first row. You can use the concrete adhesive to stagger the blocks to each other and between the first row of blocks and the second ones.


The backfill also works as a tree root barrier and offers a quick channel for water drainage. You’ll probably put a pipe behind the wall for drainage to avoid the underground water damaging your retaining wall.

install the pipe

Once you finish installing the drainage pipe (also called drain tile), place a crushed gravel layer as the use for backfill. Crushed stone, as opposed to smooth gravel, holds together and helps drive soil pressure downward (rather than outward).

build the wall block

Moreover, you can install the cap blocks, and to secure them, use two 1/4-in. beads of concrete adhesive. Cap blocks can be put flat with the wall face or with a small overhang or backset.

Once you complete all the steps to install a wall on a slope, you can add decorative designs embedded into the finished wall to give it a touch.


Building a retaining wall for our home can be simple work, however, it is not an easy one that you can finish within a few hours with little experience. You can simply install them by yourself for short walls (under 4 feet tall). For a taller wall on a slope (exceeding four feet high), it has to bear up to 20 tons of soil pressure that you must thoroughly understand how to solve this situation.

Or you can install a tiered set of retaining walls so that the wall can support less soil weight than usual. For a tiered wall system, you should place the higher wall behind the lower one at the distance twice as wall height of the lower wall. For example, if the lower wall is four feet high, the upper wall should be placed at least 8 feet far away from it.

Green Arbor Landscaping

Green Arbor Landscaping is the top-ranking company serving customers in the landscaping field in general, and the retaining wall installation field in particular. With 35-year of quality service in landscapingGreen Abor Landscaping is the superior choice for all of your outdoor living needs.

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