How Much Does a Retaining Wall Cost?
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A retaining wall is more than just another decorative element or landscaping feature. These walls serve an important function: to prevent ground from slipping and sliding. Though decorative in nature, retaining walls are a must for some areas.
Nevertheless, the big decision revolves around cost. See the full cost breakdown below. If you need some assistance with your retaining wall installation, we can help you get in touch with masonry pros near you.
Table of Contents
- Cost Of Retaining Wall
- Retaining Wall Cost Factors
- Interlocking Stones
- Uses Of Retaining Walls
- Types Of Retaining Walls
- Advantages Of Retaining Walls
- Disadvantages Of Retaining Walls
- DIY Or Hire A Pro?
- Retaining Wall Material Estimator
- Installing A Retaining Wall
- Find A Pro
Cost Of Retaining Wall
- Wood Retaining Walls: $15 per square foot
- Interlocking Concrete Retaining Walls: $20 per square foot
- Natural Stone Retaining Walls: $25 or more per square foot
The cost of a retaining wall depends on the material chosen, the overall height of the wall and the length of the wall. Wood retaining walls start at $15 per square foot, while concrete retaining walls start at $20 per square foot. Homeowners interested in using natural stone will find that those stones increase the cost to $25 or more per square foot.
In addition to the materials used, the job also requires excavating the ground and removing any dirt or surface materials from the space. This can add a few thousand dollars to the job, depending on the length of the wall. Though experts generally recommend that retaining walls sit no higher than four feet without any additional support, it's possible to have a retaining wall of up to 10 feet high. These taller walls can cost nearly $20,000 while a six-foot-wall can cost around $13,000. Decorative retaining walls and those that serve no real purpose generally cost less.
Retaining Wall Cost Factors
While the material, height and length will contribute more than anything, there are other remote factors that can increase or decrease your retaining wall cost:
Sadly, some areas of the country see more extreme weather than others, ranging from tropical storms to earthquakes. If you live in such a location, your retaining wall may require greater structural reinforcement and extensive waterproofing, both of which increase the cost to build a retaining wall.
Certain landscapes and existing retaining walls require more excavation. For example, it’s much easier to remove dirt if no retaining wall is present versus replacing an existing wall with stone and boulders already in place. If you have a retaining wall and want to save some cash on a masonry pro, remove as much of the old wall as possible.
Type of Soil
All soils were not created equal. Some soils can hold more water, while others are only ideal for very short retaining walls. In addition, bedrock, used for taller walls, can drive up your total cost.
To get a brief idea of your soil costs, refer to our soil delivery task estimator.
Some homeowners install steps for their retaining walls. Whether it’s a safety precaution or not, this project will require more materials and time and as such, raise your total retaining wall cost.
Retaining walls can be placed all over the front or backyard, however, the easier it is to access, the cheaper your project will be. Stone blocks and bags of soil are heavy. If a mason can drive the stones and bags to the exact location, the total installation time drastically reduces. If not, the job gets that much more difficult, increasing your total retaining wall price.
Those looking to save money on the project might opt for interlocking stones instead of individual pavers. These stones resemble steps with a bottom stone attached to an offset top stone. The pieces all fit together like a children's block set, making it easy to build a retaining wall. Builders will still need to dig a trench and pack down a layer of sand first, but they can easily connect the blocks together to form the wall. Most builders use a heavy hamper to tamper down the stones, and they'll add a small amount of water at the end. This lets them track the drainage and ensure that the wall drains properly.
Uses Of Retaining Walls
A retaining wall is essentially a solid wall that covers a patch of dirt. Made from brick, concrete or stone pavers, the walls are strong enough to support the dirt and keep the ground from shifting. Some homeowners use retaining walls when landscaping or building an outdoor garden or flower bed. Shorter walls arranged in a rectangular fashion or another shape create a raised flower bed that homeowners use when gardening. Many homeowners use smaller retaining walls as landscaping elements to differentiate between different types of plants and to create a focal point for their lawns.
Types Of Retaining Walls
There are several different types of retaining walls. These designs include:
- Gravity Walls
- Cantilever Retaining Walls
- Sheet Pile Retaining Walls
- Anchored Retaining Walls
- Counterfort Retaining Walls
Gravity walls feature a thinner top and a wider bottom and lean against a surface while cantilever walls feature a wide and thick base with an even wall that can support greater weight.
Sheet pile retaining walls use thick pieces of metal or wood inserted into the dirt, and most people don't know that the walls are even there. Homeowners can also choose anchored retaining walls or counterfort retaining walls if they need additional support.
Advantages Of Retaining Walls
We have already gone over a few of the benefits all retaining walls bring, but there are many more. First and foremost, retaining walls prevent steep foundations from shifting or falling. This applies to homes that sit several feet above the street and lawns that hover near the edge of a sidewalk.
Moving to the backyard, many homeowners use retaining walls to separate flower beds from other areas of the yard. They provide a good distinction from the rest of the yard if you’re adding special flowers, vegetables, a small patio or a pool.
Retaining walls can also separate your property from your neighbor’s. Property lines can get tricky, but if you have a thick retaining wall, you can ensure a healthy and calm relationship with your neighbors for years to come.
Finally, depending on the height, retaining walls provide more privacy than a typical fence and help protect your children and pets from leaving the yard. These advantages may not be top of mind, but they should be considered before installing a retaining wall.
Disadvantages Of Retaining Walls
Retaining walls aren't a one size fits all solution to shifting ground problems. While a small wall with a few layers of stones can securely hold a garden in place, that same wall won't support a mound of dirt that sits on the edge of a property. The taller the wall, the less support it offers. For taller walls, homeowners need to opt for cables placed inside the wall, or they need to choose shorter, wider walls.
Retaining walls can also shift over time, especially when not properly installed. As the dirt and ground behind the wall shifts, it puts pressure on the wall. This will eventually cause the top of the wall to shift away from the bottom and can cause the entire wall to topple. Improper drainage can lead to the foundation of the wall pushing away from the ground, creating additional issues. Other potential problems include damage from termites and other insects in wood retaining walls and cracks and chips in brick, stone or concrete retaining walls.
DIY Or Hire A Pro?
Retaining wall installation is like most landscaping projects in that active DIYers can accomplish without a landscaping or masonry pro. While the work is not easy, such as lugging stone from your truck to the yard and excavating current stone or soils, the process is not complicated.
We list out the entire process below, but as always, if you need help along the way, ImproveNet can connect you with up to four masonry pros near you.
Retaining Wall Material Estimator
If you decide to build your retaining wall yourself, you have to determine how many stones or how much wood or concrete you need to buy. More often than not, you can calculate the volume of your wall using the simple formula, V=LWH where L = length of the wall, W = width of the wall and H = height of the wall. Then, figure out the volume of each piece of wood or stone and divide the two numbers.
For a more straightforward approach, estimate the number of rows and columns you need based on the size of your wood planks or stones. Remember, most pros recommend 10% of the wall to be below ground to support the entire structure. Also, if you are using stone, don’t forget about cap blocks.
Finally, we highly recommend ordering extra materials to account for waste or poor materials. No one is perfect, so it doesn’t hurt to have a few extra pieces of stone or wood in case something goes wrong.
Installing A Retaining Wall
Before installing the pavers or stones used in the wall, it's important to properly slope the area. The ground underneath the stones should have a slight slope that keeps water from pooling up behind or under the stones. This slope helps water drain away from the area. Without the right slope, the water can saturate the ground and increase the weight of the dirt enough that it pushes the retaining wall down.
The next step involves digging a trench for the stones. This trench should be slightly wider than the stones. Contractors add a thin layer of sand or another fill material to the trench. Then, tamper the ground and ensure that the space is level. Then, place a layer of pavers on top of the sand, check that the stones remain level and add more sand if required. Add additional sand as you build up the retaining wall. Also, use sand or another material to fill in any gaps between the pavers after making the wall as high as desired.
See how the pros build retaining walls with the video below:
Find A Pro
Like many home features, retaining walls not only look great, but play a vital role in the overall health of your home. Now that you know all there is to know about retaining walls, you can confidently determine if one is right for your home.
If you’re thinking of adding a retaining wall to your landscape, ImproveNet can connect you with local masonry pros who are ready to assist.
Get free estimates from local retaining wall contractors
Last updated on Jun 13, 2018