How To Make Retaining Walls Using Concrete Bags

Jessica Stone
by Jessica Stone
Retaining walls are often necessary, but they can be expensive and annoying to build unless you are resourceful. One of the best ways to save money and make use of readily available materials is using concrete bags for a retaining wall and letting them biodegrade. Whether it be drainage problems or erosion, you likely need a retaining wall, so let’s explore how you can make one with concrete bags.

Retaining walls are constructed on a property to help hold back soil and other forms of dirt. You’ll often find these structures on a hilly freeway, around stairways, in gardens or where multiple levels to a landscape are needed.

While the most conventional retaining wall involves the use of concrete blocks, stone or poured concrete, these options can be rather pricey and difficult to install. Thankfully, we have a much easier, more cost-effective way to build a retaining wall using stacked 60-pound concrete bags.

Building this type of retaining wall is as simple as stacking concrete bags like Legos and wetting them down with a hose. As time goes on, the concrete bags will biodegrade, resulting in a permanent, sophisticated retaining wall.

We’ve outlined all the necessary steps you can follow to successfully construct a retaining wall out of concrete bags.

Do You Need Retaining Wall Installers?

Get free, zero-commitment quotes from pro contractors near you.

What Is a Retaining Wall?

A retaining wall is a structure that is constructed to hold soil in place behind it. It retains the soil on a slope, allowing for flat areas instead of extensive, natural inclines. They are built using a variety of differing materials and can range from only a few inches in height to several feet, depending on the property.

In addition to heights, retaining walls come in many different designs and appearances. They can be designed as a straight wall or even a curved wall to add character to a landscape. The average retaining wall is around four feet tall and under since anything taller typically requires permits and the assistance of an engineer.

How Does a Retaining Wall Work?

The pressure that the soil places on the retaining wall can be immense, requiring these structures to work in a sophisticated way. In general, for a retaining wall to function correctly, it needs to be strong enough to withstand the weight and pressure of the soil that would otherwise remain sloped if the wall was not in place.

Without a retaining wall, the soil would succumb to gravity and fall directly down the incline. Retaining walls are generally built on a minor inward lean so the pressure from the soil doesn’t cause the wall to lean out.

It’s also essential that they are carefully designed to prevent water from building up behind them, adding to the pressure and potentially damaging the wall. To compensate, some designs will implement a very hi-tech drain system however, all will typically require some form of drainage.

How to Make a Retaining Wall Out of Concrete Bags

As opposed to more traditional materials, the steps for constructing a retaining wall from concrete bags is very simple and straightforward. Rather than having to mess around with mortar, you simply stack and construct the wall using the concrete that is still in the bags.

  • Using a shovel, flatten the ground where you’ll be installing your retaining well. Make sure that it is completely level. If you’re working in a very large or substantially uneven area, it may require that you use something more sophisticated, like a tractor.
  • Begin laying down the first level of concrete bags in the space where you intend to build the wall. Yes, keep the concrete inside of the packaging.
  • Stack the next level of bags on top of the first. Stagger this second level by placing the center of the bags on this layer over where two bags on the first level meet. It will look very similar to a traditional brick pattern.
  • Shift the bags backward about 0.5 to 1 inch toward the slope of the hill you’re building on. This will help give your retaining wall additional strength and durability.
  • Repeat this pattern of stacking until you’ve reached five levels of concrete bags; or enough levels to equal your desired height.
  • At this point, for extra reinforcement, you can choose to drive rebar into each of the bags.
  • Spray the bags with a hose, taking special care to make sure that you thoroughly saturate each bag.
  • Allow the bags to dry for roughly 24 to 48 hours.
  • Once the concrete has cured, you can wait for the paper of the bag to biodegrade, burn it off, or peel it yourself.

If you don’t find the shape of the standard concrete bags appealing, you can take the extra time to re-bag the concrete into smaller “lunch-sized” bags.

Considering Drainage

Since the purpose of a retaining wall is to transform a sloped surface into a flat one, they often collect irrigation and rain water. When water starts to accumulate behind a retaining wall, pressure increases in the soil and places more weight on the wall.

Without the necessary drainage, your retaining wall can crack, expand, or fail completely. To prevent any of these drainage problems, implement the following measures:

  • Weep holes: Weep holes are one of the easiest ways to achieve proper drainage with a retaining wall. Small holes drilled in consistent intervals throughout the wall will relieve the pressure by allowing water to escape through the holes.
  • Perforated drainage pipe: These pipes are placed at the base of the retaining wall, buried in the soil. It has several holes drilled around it for it to collect water has it travels through the soil.
  • Granular soil: Granular soil is another option to help water move easily toward both the weep holes and drainage pipe. It has no cohesive strength and coarse grains, allowing alternative drainage systems to collect water and banish it from the area.

How to Know if Your Yard Needs a Retaining Wall

Now that you have a greater understanding of the step-by-step process of constructing a retaining wall from concrete bags, it’s important to understand whether or not your property will actually benefit from one. The following are some indications that your yard may need a retaining wall.

1. You are experiencing issues with drainage.

If you have a considerable amount of standing water in your garden, this should be corrected. These areas of water can drown the roots of your plants and cause waterlogging and rot, creating a breeding ground for pests.

With their built-in drainage system, a retaining wall can help alleviate your water problems. They work by breaking up the levels on your property and filter water towards drains and other waterways.

Water drainage systems are vital to the success of retaining walls, as the material they are made out of alone is not sufficiently porous for water to pass through.

2. You have erosion concerns.

When you have a home that is built on a property with soil that doesn’t have a lot of roots holding it together, erosion can be expected. It’s frustrating to have to replant a garden because of errant mud and water erosion.

A retaining wall can help to maintain the structural integrity of the soil on your property. It does this by decreasing the angle of the slope on your property and holding back soil. Installing a retaining wall will effectively channel water away, reducing the threat of erosion.

3. You need flat land to grow greenery.

If your home sits on a slope or has some sort of multi-level landscape, you may be thinking that growing a garden is out of the question. Installing a retaining wall can be your number one defense against plants getting uprooted by gravity.

Whatever purpose for needing more usable land, retaining walls help to create flat areas where you can build terraces, grow gardens or just get the most out of your property.

4. You need a creative way to separate and add levels to your backyard.

If you and your family spend a lot of time in your backyard doing a variety of different activities, you may be looking for ways to divide the space. For example, you may not want the yard where your dog runs around encroaching on your patio area or other entertaining space.

Retaining walls can be used to visually separate your property into multiple zones for activities.

5. You’re worried about your foundation.

Not only can erosion destroy the plants in your garden, it can always cause damage to your home’s foundation. The soil on the surface and below are all affected by soil erosion.

Once the soil deep below the surface begins to erode, it’ll leave large voids under the ground. If your home’s foundation is near one of these gaps, the stability becomes compromised. Also, water can seep into these voids and crack the foundation.

A properly, well-constructed retaining wall can keep your soil in place, add functionality to your property, effectively prevent erosion, improve drainage and reduce the strain on your foundation.

Do You Need Retaining Wall Installers?

Get free, zero-commitment quotes from pro contractors near you.

Wrapping It Up

If you’re looking for a simple, budget-friendly way to construct a retaining wall, look no further than concrete bags. Building a retaining wall out of concrete bags is as easy as stacking the pieces and spraying them with a hose. Over time, the material of the bags will biodegrade and you’ll be left with a solid, permanent retaining wall.

Whether you’re looking to increase the usable area on your land, prevent erosion, improve drainage or protect your foundation, a retaining wall built from concrete bags is an excellent solution.

Related Guides

Jessica Stone
Jessica Stone

Jessica considers herself a home improvement and design enthusiast. She grew up surrounded by constant home improvement projects and owes most of what she knows to helping her dad renovate her childhood home. Being a Los Angeles resident, Jessica spends a lot of her time looking for her next DIY project and sharing her love for home design.

More by Jessica Stone