THE POWER OF THE RETAINING WALL

Holding back the Earth can be tough, but retaining walls can get the job done. Featured in both back and front yards, these walls can help bring your property together. If you have an area you want to create or a property with hills…a retaining wall is definitely for you!

What Is A Retaining Wall?

A retaining wall is a type of wall that holds back soil, water, or anything else that could erode. There are various materials that may be used, but retaining walls are used to create grade differences.

Retaining Wall Blocks

There are a few different types of retaining wall blocks you can use to build your retaining wall. Each has a unique appearance and various reasons as to why people choose it. Here are the top 4 choices!

CONCRETE BLOCK RETAINING WALL

Segmental retaining walls, commonly referred to as SRW, are the most popular of the retaining wall choices. They offer a vast range of colors and textures to match any design criteria. Segmental retaining walls are built without mortar or frost-free footers. The lack of mortar doesn’t mean that these walls are weak, though! These flexible systems last many decades, are capable of supporting parking areas, buildings, etc, and can be over 80’ tall!

NATURAL STONE RETAINING WALL

The look of stone is, by far, the biggest reason people choose this option. You can have a symmetrical wall with evenly sized stones, or you can select mismatched sizes and shapes of stones to create your wall. Natural stone may be dry-laid and should be limited in height. It may also be mortared together or used as a veneer on a mortared block wall.

WOOD RETAINING WALLs

These retaining walls are definitely one of the less expensive choices on the list. A wood retaining wall is also the most common choice for DIY projects.

These types of walls also come with the caveat of a short life span. Things like wood rot tend to come in and ruin a once great wall. There is also the consideration of strength. A stone or block wall can be adequately designed to withstand the pressure of retaining soil; wooden walls should not be used in critical structures.

CONCRETE RETAINING WALL

A poured concrete wall has an advantage in specific scenarios. They may be a better choice in areas with frequent flooding with the risk of scouring away the base. Poured walls may be veneered with stone or brick to create a more attractive wall.

BRICK RETAINING WALL

Brick retaining walls are naturally warmer in color, so they add a different level of invitation to your property. Brick keeps this color and is very easy to maintain. Considered to be very eco-friendly, this retaining wall is also fire-resistant.

The downside with brick retaining walls is the cost. Where wood falls into a less expensive category, brick is the opposite.

Retaining Wall Cost

Retaining walls can cost anywhere from $15 per square foot all the way to $100+ per square foot. The price depends on the type and variation of the material you are using. Remember that the actual wall material is only a small portion of the cost. There are many other costs involved in a successful retaining wall project, including base and drainage stone, drain pipe, adhesives, geo-grid, geo-textile, and of course, labor if you plan to hire somebody for the project!

Retaining Wall Specs

There are often questions about DIY retaining walls to be aware of. Here are the top 5 questions about the specs of your retaining wall to keep in mind as you are constructing it.

• How thick should the base be?
  • You may use unreinforced concrete, dense-graded stone, or open-graded stone for a segmental retaining wall. The base should always be a minimum of 6” thick and extend a minimum of 6” in front and behind the block.
• How deep should the base course be buried?
  • This term is also called embedment, and on any segmental or natural stone wall, the base course must be buried a minimum of 6” or 10% of the wall height. If there are unstable soils at the face of the wall, surcharges like a driveway, steep slopes above or below the wall, or other such factors, up to 36” of the wall may need to be buried.
• Do I need a drainage system?
  • Yes! No matter the height or width of your wall, you will need to think about the drainage. For information on how to get this done, check out this article. Walls should have a minimum of 12” of clean stone gravel behind them for drainage, and some applications may call for up to 36” of clean stone! Clean stone may also be called ¾” clean, 2B, #57, or #67 stone.

• How tall can I build my retaining wall?
  • Building codes require any walls over 48” high to be engineered. Some municipalities may require an engineer’s review for shorter walls as well. Any block or stone wall over 30” high generally will need some kind of stabilization such as geo-grid.
• How do I build a retaining wall on a slope?
  • Excavate a trench at least 12” below the grade in front of the wall.
  • Compact the trench
  • Install base material, typically a dense graded aggregate such as 2A modified or clean stone such as 2B or #57.
  • Compact the base material. Depending on the size of the compactor, you may need to install the base in two lifts. If so, place the second layer of gravel, screed it level, and recompact.
  • Place the base course of the block. Ensure that they are level from side to side as well as front to back.
  • Fill in front and behind the base course and compact.
  • Place the next course of block, place gravel and fill material behind the wall, and compact after placing each course.
• Are deadmans needed in a retaining wall?
  • Deadmen are used only in timber wall construction. While deadmen are effective, wooden walls still tend to rot and lean from the lateral soil pressures. Geo-grid is used in SRW block walls for stabilization.

Retaining Wall Ideas

Here are a few popular retaining wall ideas that come up when we landscape. You can customize your size and location when choosing any one of these options.

POOL RETAINING WALL

Retaining walls are a great way to add dimension to your pool area. You can have a garden behind and above your swimming area with a simple retaining wall. We have also seen these walls act as water features into the pool or as supports for slide installation.

FLOWER BED RETAINING WALL

Another great way to utilize your retaining wall is by placing flowers above it on one side. This will give clear separation between one area and another. The earth tones of the retaining wall can also allow the color of the flowers to pop on your property. Interested in more hardscaped flower bed ideas? Check out this blog!

DRIVEWAY RETAINING WALL

A driveway retaining wall is perfect for a sloped front yard. If you have just recently put in a driveway (or want to), you can give your property some dimension with a driveway retaining wall. The wall may be supporting the driveway itself, or it may be used to cut into the bank and create a level area for the driveway.

RETAINING WALL WITH STAIRS

A retaining wall complimented by stairs is useful and attractive. The retaining wall can increase in elevation as well as length. Don’t forget to follow local codes for step riser and tread dimensions as well as fall protection. Generally, a riser of 4-8” high and 10”+ treads are acceptable for residential projects. Risers and treads should be uniform so they are not a trip hazard.

WATER FEATURES

Retaining walls can also make the perfect backdrop for water features in your yard. Whether a fountain, waterfall, or pond…you can utilize a retaining wall to surround your water feature for added effect. SRW and brick walls are best suited for formal water features, especially those with sheer descents.

Retaining Wall Styles

When trying to find the best retaining wall for your property, there are a few different styles you can begin with. Your retaining wall style may depend on how you use it, but you can incorporate different designs into most projects.

IRREGULAR

This retaining wall style can also be called “modern.” It uses different materials in non-symmetrical ways to create a retaining wall look that no one else has. These are used in both back and front yards to create a custom and personalized look.

DECORATIVE

Decorative walls may be free-standing, meaning they are not actually retaining soil. These walls can add a lot of visual appeals.

FENCE

A tall freestanding wall can separate your property from public property and serve as a fence. Generally, any freestanding wall over 30” high will require a frost-free footer. Walls may also be used to deter small animals.

TIERED

Tiered walls are complex systems with significant reinforcement required to create a stable structure. Tiered retaining walls are generally used when there is a considerable difference in height between sections of your yard. Instead of having a very high wall, you break it down into smaller, aesthetically pleasing sections. This also allows you to plant flowers, trees, or other vegetation on each wall level.

How Much Weight Can A Retaining Wall Hold?

Retaining walls can hold vast amounts of weight. Walls should be matched to their intended loads. It will require additional reinforcement if your wall supports significant loads such as a pool, driveway, commercial traffic, hot tub, or a steep slope above the wall. Larger blocks, more embedment, more geogrid, and other measures may be required to build a wall that will stand the test of time.

Retaining Wall Drainage

Drainage for a retaining wall is essential. When excess water builds, it can cause a retaining wall to move or collapse because of hydrostatic pressure. During a catastrophic failure due to hydrostatic pressure, the block can be flung up to 80’ away from the blowout. Don’t risk failure from lack of drainage! If you are hiring a company like us to build a retaining wall for you, we will make sure the drain system is set up correctly. If you are doing it yourself, keep the following in mind:

• Include a minimum of 12” of clean stone behind the wall
• Consider filter fabric to prevent clogging of the clean stone, or increase the clean stone to 24-36” behind the wall.
• Include a Drainage Pipe that daylights every 40’.

Retaining Wall Repair

There are a few issues that may be plaguing your existing retaining wall. Here are some of the problems that arise with retaining walls.

• Drainage Issues
  • Failures due to lack of drainage may include bulging, toppling, collapsing, or sliding. These symptoms may also be due to insufficient reinforcement.
• Foundation Problems
  • Settling of the wall may occur from inadequate compaction of subgrade and base materials, insufficient base depth, and weak or saturated soils. This requires tearing the wall down to the bottom to repair the foundation.
• Contractor Problems
  • If you are noticing other issues with your retaining wall (quality, material issues, etc.), it may be important to contact a professional or try and remedy the problem before it gets worse.

Retaining Wall Conclusion

We would love to help you install a retaining wall to give your yard a fantastic look. If you need help fixing a current one or would like to talk about a new retaining wall, we are here to help! Contact us to get a quote and discuss how to get your dream yard!