Cinder Block Retaining Walls

Installing a retaining wall in your home or business landscape not only can increase your usable outdoor space, but can also add visual interest and even boost the resale value of your property.

If you’re considering a cinder block retaining wall, choosing the right type of cinder or concrete retaining wall blocks when building your retaining wall can be important to insure both safety and longevity.

A cinder block retaining wall is often viewed as the equivalent of a concrete block retaining wall, but there is much more to know about your choice of materials than merely their appearance.

Cinder Block Retaining Walls

Cinder Blocks Vs. Concrete Blocks

Cinder blocks are often referred to as as a type of “concrete block”. However, while terms can be rather ambiguous, each type can have unique features that distinguish them when used as retaining wall blocks.

Composition

A hollow, rectangular-shaped cinder block is normally made of a mix of concrete and coal cinders (ash), while a concrete block is typically made of a mix of cement, sand, water, crushed stone, and/or gravel. Either can be used as blocks for a retaining wall, but there are differences to consider.

Weight

A cinder block generally weighs significantly less than a concrete block and is therefor easier to work with. However, because they are lightweight, their pressure-bearing ability is not as high. They are available in standard dimensions, so you can use them interchangeably.

One downside to cinder blocks is that it is becoming a challenge to find them in some areas. Builders and homeowners have a broad selection of other materials to consider for retaining walls, including concrete blocks, poured concrete, pressure-treated wood, and natural stone.

Concrete block retaining wall and raised planter

Concrete Block Retaining Walls

For some construction projects concrete block retaining walls may be a more suitable option. They are heavier, extremely durable, and more capable of handling pressure.

In some cases, concrete blocks can be added to a cinder block retaining wall because of their superior tensile strength, to ensure the structure is properly reinforced for longevity.

Primary Uses For Cinder Block Retaining Walls

The main purpose of a retaining wall is to to hold back the earth behind it, and to create a straight, sturdy, and flat surface at it’s front. Retaining walls can also be used as a safety feature for slopes exceeding 35 degrees that are at risk of becoming unstable. People often also use retaining walls to add aesthetic value and to create or expand a beautiful outdoor space.

The kind of wall block utilized in the construction of a retaining wall may depend on your budget and individual preferences. If you are installing a wall for aesthetic reasons only, you have more flexibility if do not need to stabilize an unsafe area of ground or level a slope. In this case, safety and functionality will be key.

The options are endless; however, serious advanced planning and preparing of the area is usually necessary before construction can begin.

Cinder Blocks for Retaining Walls – Interesting Facts

  • They are generally manufactured from concrete and ash
  • They are relatively lightweight due to the ash aggregate in their composition
  • Their tensile strength is low
  • Currently cinder blocks are no longer produced in large quantities, which makes them relatively more difficult to find.
  • They are not as strong and durable as concrete blocks, and may not be suitable for some projects without the addition of mortar fill and/or rebar within their hollow spaces to add strength.
  • Proper designing of cinder block retaining walls is crucial for walls higher than four feet, especially with sloping ground behind them. Improper construction can result in gradual structural failure like break-up or buckling over time, often requiring complete replacement. This is a major reason why most local building codes require an engineering design for retaining walls of 4 feet or taller.

Drawbacks of Cinder Block Retaining Walls

The advantages of cinder block wall construction far outweigh the disadvantages; however, there are a few drawbacks worth mentioning:

  • Superior quality cinder blocks may be difficult to find in quantity.
  • They do not tolerate severe weather conditions well; therefore, ensure proper safety precautions and regulations are followed when constructing an outdoor structure. It may be necessary to obtain a building permit and an engineering design, particularly for walls of more than 4 feet in height.
  • They are not as strong or durable as concrete blocks.
  • Repairs can be costly.

Things To Avoid When Building a Cinder Block Retaining Wall

  • Never build a DIY retaining wall higher than three feet, as it may not be strong enough to withstand pressure from the earth behind it, potentially posing a safety risk.
  • Always check the draining capacity of the area where you want to install the retaining wall. A build-up of too much water behind the wall can saturate the soil, which may compromise the structure. It is not uncommon for retaining walls to fail because of poor drainage. The saturated soil can push the wall beyond its maximum load capacity.
  • Failure to hire a qualified and experienced engineering company to help with drafting the engineering design for your retaining wall, can lead to a waste of time and money, or worse, compromising the safety of your property.

Building a Retaining Wall on a Slope

The process for cinder wall construction on a slope is somewhat different and trickier than building the wall on a flat surface, since it will need to be significantly stronger. When in doubt it is always best to obtain a professional engineering design and hire a qualified and experienced contractor to install your retaining wall.

4 Essential Steps For Designing a Retaining Wall

1. Choosing the Location of Your Wall

Decide on an area where back fill and soil excavation can be kept to a minimum, if possible. Evaluate the existing site features and optimize drainage and grading patterns.

2. Plan an Appropriate Height for Your Retaining Wall

Scrutinizing the area and identifying slopes below and above the wall and calculating the retaining wall’s height at the tallest position, is an essential step.

3. Consider Structural Requirements and Material Choices

Decide on any reinforcement requirements that your wall will need and which material types would be suitable for it

4. Add Cap Stones to Finish Off the Top of Your Wall

Capstones of various types can be used to finish off the top of your retaining wall, to enhance its appearance and/or functionality.

5. Calculate the Complete Wall Structure

Before building can commence, you need to calculate the necessary wall setback and evaluate the space available for building the retaining wall.

A qualified engineering company such as Xpress Engineering can assist you with the retaining wall design process.

Cap stones for a cinder block retaining wall
Cinder blocks

Average Cinder Block Costs

A Standard cinder block typically costs between $1 to $5 per block, including slump blocks, hollow blocks, concrete blocks, half blocks, rounded blocks, and other types of CMUs (concrete masonry units).

Decorative cinder blocks, such as split-faced blocks, may cost in the region of $2 – $5 per block. CMU or cinder blocks are popularly used in various home construction developments.

A standard cinder block may commonly be found between $1.25 and $2.50 per block, whereas the larger CMU blocks may be priced between $2 to $4 per block.

Why It’s Worth Considering Cinder Block Walls

The different types of retaining wall each come with their own set of special features and benefits. Cinder block retaining walls are among the most robust type of wall you can build. They can withstand most storms and hurricanes, and little or no maintenance is necessary. They may also be a lot friendlier on your wallet.

Benefits of Cinder Block Retaining Walls

  • Price – cinder blocks are typically more cost-effective than concrete block or other building materials for retaining walls.
  • Strength – even though they are not as strong as concrete blocks, cinder blocks are still quite strong and should last a very long time when properly designed and built. They are among the most robust types of walls commonly used for residential areas.
  • Lifespan – cinder block retaining walls can last for centuries due to their durability, especially if properly designed and installed by a qualified contractor.
  • Environmentally friendly – they are typically made from non-harmful materials that are safe for use in the environment without compromising structural strength.

Cinder block wall with plaster finish

Certain features like waterproofing sealant, decorative veneers and finishes can improve functionality or appearance, but may also increase the cost of your cinder block wall. However, such features are often well worth some added cost. You can really dress up your cinder block wall by adding surface veneers or finishes, including stucco, paint, stone, brick or plaster.

Cinder block wall with plaster finish

Retaining Wall Ideas

Many people invest in a block retaining wall for aesthetic reasons, adding different textures and interesting features. Another purpose may be to create more useable space within your landscape, or even to create different sections. For instance, you can separate the playing area from the lounge space with a design with two levels, separated by a retaining wall. You can also use a retaining wall to define the boundaries of your property or protect a driveway from adjoining slopes.

Block retaining walls may be very useful for creating flower beds and making your outdoor space more attractive. In some scenarios, your wall can double as a seating place when built at the appropriate height.

Other Landscaping Design Ideas

  • Making your landscape more usable by adding terraces for hillside or sloped yards.
  • Breaking up your lawn by adding raised beds or adding new planting areas, colors and textures, subsequently saving time and expenses on lawn maintenance.
  • Creating multilevel plantings with stair-stepped retaining walls.
  • Making your outdoor entertainment space more functional by planning your design to include nooks for the cooking area, dining space, fire pit, and other entertainment areas.
  • Beautifying your sidewalk or driveway by installing a retaining wall and raised flower beds next to them.
  • Incorporating a raised bed with a water feature or pond.

Is a Cinder Block Retaining Wall Right for You?

Cinder block retaining walls are a popular choice for commercial properties and residential homes alike. They offer a fantastic way to add structural and aesthetic value to your property and can be built in a broad range of designs, shapes and sizes, with various attractive features and finishes.

Whether cinder blocks are the perfect fit for you depends on your individual needs. If you’re looking for a retaining wall that is durable, versatile, and able to withstand the elements, then cinder blocks certainly should be considered.

Why It’s Best To Hire A Contractor For The Job

Cinder block walls are relatively easy to install, but it’s worth putting the safety of your family and the longevity of your wall in the capable hands of a contractor that has the necessary knowledge and expertise to do the installation.

Professional Engineering Retaining Wall Design – Fast and Affordable

Whichever material you choose for your retaining wall project, keep in mind that most local building codes require an engineering design for any retaining wall of 4 feet or more in height. And even for shorter walls, a design from a trained structural engineer is highly recommended to ensure the security and longevity of your wall.

We can provide a certified engineer design for you within 24 hours for just $350. Submit your Design Request here, or contact us if you have any questions or unique requirements.