“How To Build a Retaining Wall?” is one of the most commonly asked retaining-wall-related questions on the internet.

Building of retaining wall

Regardless of what material you decide to use for your DIY wall project, whether you want a wood retaining wall, concrete blocks, or any other material, our step-by-step guide will apply to all retaining wall systems.

It’s simple to dry stack wall blocks. It is, however, challenging to maintain them stacked for years.

Keep reading this article to know how to properly build a wall knowing that your DIY wall must have a sturdy base and hard backfill to maintain stability.

How To Build A Retaining Wall On Your Own

– Step 1: Excavate Your Space

You’ll have to start excavating before you can start building. The amount of earth you’ll need to excavate is determined by the height of your wall and the type of blocks you’ll use. We recommend around 12 inches below ground level for a six inches compacted base of gravel and six inches of embedded wall block in this how-to lesson.

– Step 2: Lay A Substantial Gravel Base

Next lay a six inches base of 34 inches minus road gravel in two inches lifts after excavation.

Substantial Gravel Base

Then, move the gravel with a wheelbarrow, but depending on the size of your retaining wall, a walk-behind front-end loader or a small tractor with front-end loading capacity may be more appropriate if it is possible to get your hands on.

We suggest using a garden rake to spread the gravel as evenly as possible for smooth compaction after placing enough pebbles in the hole.

– Step 3: Compact The Gravel With A Compactor

Depending on your compactor’s rating, you may need to space out your base in a few lifts. Ideally, the ground should be compacted three times for this job, compressing the floor after every two inches of gravel you lay.

“How much gravel can my plate crusher flatten at one time?” you might wonder. As a general rule, a plate compactor can compact as many inches of gravel as the number of persons needed to pick it up in one go.

Try only to compress two inches of gravel at a time if your plate compactor requires two workers to pick it up and adjust as per the requirements of your compactor.

– Step 4: Pinup Filter Fabric

Filter fabric is an integral part of the retaining wall construction process. It allows water to pass through while keeping dirt, bark dust, and other landscaping from moving into the gravel.

To begin, measure and cut the length of the area to be covered. We recommend cutting the filter fabric twice the height of your wall to drape it over your backfill once you’re done. This step is necessary to ensure that any dirt or landscaping you place on top of your wall does not get caught in the reinforced backfill.

You can use the entire width of the fabric roll as your height in this project. If you’re constructing a tall wall, you can always add a strip of filter cloth at the top to compensate. Pining filter cloth is a straightforward process. 

Use a sufficient number of landscaping staples to keep it in place while constructing your wall. You’ll pull the staples out once you’re finished so you can fold the filter fabric on top of the backfill. That’s all there is to it. You’ve laid the groundwork for a reinforced retaining wall with compacted gravel and a filter cloth barrier.

– Step 5: Install A Perforated Pipe For Water Drainage

Drainage that has to go behind or under your wall will occur no matter where you reside, especially in the Pacific Northwest.

Tiered Retaining Wall

Install the perforated piping at the back of your wall at a gradient that will allow water to drain through the pipe as needed. You’ll bury the line (save the ends) as you add gravel backfill to keep it in place.

– Step 6: Lay The First Layer Of Blocks And Fill It With Gravel

Your retaining wall area is now ready to receive the first course of blocks. Install a string line where you’ll be stacking blocks before you lay blocks to assist you in building a straight and level, initial course.

You’ll need to chip off the lip if you’re using a regular 616 inch manor stone, also known as a cinder block. You’ll need a traditional hammer for this, which you can see in the image above. The reason for this hammar is that it’ll be at the bottom of your first layer, it doesn’t have to be perfect.

Use a tiny torpedo level to ensure that each block is level, front-to-back, and side-to-side as you place them on a gravel base. Fill the retaining wall blocks with gravel after laying the first course to ensure solidity.

– Step 7: Compact The First Layer For A Sturdy Foundation

After laying your first course of retaining wall blocks and filling them with gravel, backfill with another six inches of gravel. As stated in steps two and three, rake and compact.

– Step 8: Place Geogrid To Add To The Stability Of The Wall

Placing geogrid between courses is another crucial step in fortifying your wall. Geogrid creates a framework within your backfill that keeps your gravel (and your wall) in place.

The Stability Of The Wall

The width of a typical geogrid roll is six feet. You might have to overlap the grid, as seen below, depending on the length of your wall. Shovel a thin layer of gravel between the overlaps to provide stability if you need to overlap the grid.

– Step 9: Stack, Compact, And Grid

You can repeat steps six through eight until your wall is the proper height after laying your first course, backfilled with gravel, and installing geogrid.

– Step 10: Cap Off Your Retaining Wall

The final step is to safeguard your gravel backfill, unpinning the filter fabric and folding it over the backfill. After installing your filter cloth, top it up with landscaping, such as bark dust, ornamental rock, or topsoil. That is how a beautiful and stable retaining wall system is created.

 

How To Build A Retaining Wall On A Slope Or Hill

Once you’ve decided on building a retaining wall on a slope, the first undertaking is to construct the numerous step-ups you’ll need for the property. The procedure starts at the bottom, with the construction of the lowest wall elevation.

Although each site has its unique features, you’ll usually dig a 24-inch-wide base trench. Allow six inches plus an extra inch for every foot of wall height for the number of buried bricks or materials needed to establish the depth.

If your wall is less than four feet tall, the base trench can be 18 inches wide and four inches deep, plus any additional space required for buried blocks. The ditch must also extend far enough into the hill to cover an entire block. An engineer is frequently required to complete the initial steps if there is a slope below the beginning of the wall.

– Step 1: Start With The Trench Compact and Level

You’ll need to compact and level the ground after you’ve finished the base trench. This phase of the job typically necessitates the use of a plate compactor. It takes at least two passes to get a satisfactory result, and it can take up to four to six keys to lay the correct foundation.

After you’ve finished this step, you can install the wall drainage pipe at the back of the trench’s lowest point.

– Step 2: Install the Wall Rock

At least 6 inches of wall rock should be placed along the base trench. Once it’s in place and level, use the plate compactor to make at least two additional passes to guarantee you have the durability you need for your project.

– Step 3: Excavate the Second Level

You’re ready to build the second level of your retaining wall on a slope after digging the trench.

Excavate the Second Level

Ensure there’s adequate room for the buried rock and the material in this spot. After putting everything in position, condense the space and make sure it’s level.

– Step 4: Place the Base Layer of Blocks

Once the trench and step-up area are done, the base course of blocks can be placed on the base material. With each addition, check for the level to make sure your work is steady and supported.

Concrete blocks assist in filling the hollow cores for extra strength. Once you’ve finished the construction, the blocks and base of your following step-up level should be equal.

– Step 5: Behind the Blocks, Start Compacting the Wall Rock

After installing the blocks, run the plate compactor down the wall rock to make sure the slope anchors are secure. You’ll keep working until you reach the top of the grade.

Please remember that each step-up level’s blocks must be buried to achieve the correct base depth. If you skip this stage, erosion will eventually cause the wall to crumble.

– Step 6: Fill in the Step Up Areas

Due to the slope, you’ll probably have gaps to fill with dirt or other gardening materials once you finish building the retaining wall.

Fill in the Step Up Areas

The goal is to achieve a flat, even surface that suits your requirements. These materials don’t need to be compacted, primarily if they’ll be used for garden beds or other elements.

FAQ

– What Materials Are Best For Retaining Walls?

Retaining walls are constructed using a mix of different materials. Concrete is a common material for retaining walls, although additional options include railroad ties or treated wood and wall stones, natural stones, bricks, and concrete blocks. Wood, while inexpensive, has the lowest lifespan due to its sensitivity to decomposition.

Stones, pebbles, and boulders, on the other hand, can help to build an aesthetically beautiful retaining wall, but they come with a slightly higher price tag and require some upkeep to prevent erosion. Masonry blocks are a low-maintenance alternative in a wide range of sizes and colors.

– How Much Does It Cost To Construct A Retaining Wall?

A retaining wall should cost between $3,000 and $8,000 in most cases. The final cost of your wall will be determined by how tall you want it to be and what materials you use.

A cinder block wall should cost between $10 and $12 per square foot, whereas poured concrete will cost nearly twice.

However, because labor is usually $25 per square foot in addition to materials, you might want to consider bringing some friends over to help instead.

– When to Consult An Engineer When Building a Slope?

There are various aspects to consider when deciding whether or not to hire a professional engineer to build the retaining wall.

Consult An Engineer

The first is the wall’s height; most localities demand a permit and design plan if the wall is above four feet from a structural engineer. Engineers are also required to design and permit terraced walls.

Conclusion

While building a retaining wall can sound like a fun project that you can get help from friends on, you must remember a few crucial points to avoid making mistakes that could have dire consequences.

  • Make sure you conduct adequate research before committing to this project.
  • It is always better to consult an engineer for the first few steps of the process, even if hiring one for the whole isn’t possible.
  • Ensure that you follow through on each step before moving on to the next because the slightest negligence could cause structural instability.
  • Make sure you use suitable materials for your retaining wall, keeping in mind the function of your wall, the wall design, and the elements in its surrounding that it will interact with.

Once you know everything about building your retaining wall, undertaking this project will be a piece of cake, provided you perform every step correctly. Good Luck!

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