Retaining Walls

we specialize in Retaining walls that add function and beauty
Our team of experienced professionals has been serving the greater Seattle area for years, providing top-notch retaining wall installation services to homeowners and businesses alike.
Seattle Sustainable Landscapes: Expert Installation of Retaining Walls in the Greater Seattle Area
Are you in need of a retaining wall to add function and beauty to your landscape? Look no further than Seattle Sustainable Landscapes. Whether you need a small wall to define a boundary or a large wall to hold back soil, we have the expertise and resources to get the job done right. Read on to learn more about how retaining walls can help transform your outdoor space.
Permitting Requirements for Retaining Walls over 4 Feet in Height
Retaining walls serve a vital role in landscaping, providing support and structure to help contain soil and prevent erosion. However, if your retaining wall is over 4 feet in height, there may be permitting requirements to consider before starting your project. In general, retaining walls over 4 feet tall are considered “structures” by most building codes and may require a building permit.
One way to avoid these permitting requirements is to build a series of shorter retaining walls, known as terraced retaining walls. This can be an effective way to create the same visual impact as a single, tall wall while staying within the height limits. If you are considering a retaining wall project and have questions about permitting requirements, be sure to consult with a local building department or a licensed professional for guidance.
Retaining Walls: A Practical and Attractive Landscaping Solution
Retaining walls serve a number of important functions, there are several reasons why property owners want to build a retaining wall:
- Hillside retention: Retaining walls can help to prevent soil erosion by holding back soil on slopes and preventing it from sliding or collapsing.
- Creating level areas: Retaining walls can be used to create level areas in areas where the land is sloped or uneven. This can increase the functionality of the yard. Often homeowners want to provide clear spaces creating, planted areas, play areas, parking areas, etc. Creating more level areas can increase the usable space.
- Controlling water flow: Retaining walls can help to redirect water flow and prevent erosion caused by water. This can be particularly important in areas prone to flooding or heavy rainfall.
- Enhancing the appearance of a property: Retaining walls can be used to create a visually appealing boundary or divide different areas of a property.
- Increasing property value: A well-built retaining wall can enhance the appearance of a property and increase its value.
Types of Retaining Walls for Your Landscape
Seattle Sustainable Landscapes’ favorite styles of retaining walls.
- Natural stone – this requires a very skilled process called ‘dry stacking.’ Each stone is unique in its shape and size so it takes great attention and patience to ensure the wall is built in an attractive and secure manner.
- Manufactured Stone, Brick, or Concrete – this is the most common style and easiest to implement as the stones are uniform creating a simple design and stacking, they can be used with various types of manufactured materials.
- Repurposed concrete – we love to reuse concrete from demo projects, there are times we are able to use material removed from another area on the property and repurpose it by using it in a retaining wall.
- Pressure Treated Lumber – there is an option of using wood as a retaining wall, Pressure Treated Lumber is what is used for fence posts or railroad ties.
Of the four styles, manufactured products are the fastest and cheapest option and there is an incredible amount of variety between all of the textures, colors, shapes, and sizes of material to use. Natural stone retaining walls are very impressive when done correctly.
Professional Installation for Retaining Walls: What to Expect
Installing a retaining wall can be a complex project that requires careful planning and attention to detail. Feel free to reach out, but here is a step-by-step guide for installing a retaining wall:
- Determine the location and design of the retaining wall: Consider the slope of the land, the height and length of the wall, the materials you will use, and any drainage or drainage control needs. You may need to seek the assistance of a professional engineer or landscaper to help with the design and planning of the wall.
- Obtain any necessary permits: Check with your local building department to see if you need a permit for your retaining wall project. Follow all local building codes and regulations. Ideally, build a retaining wall that does not require permits, stay under 4 vertical feet per retaining wall – use multiple levels when necessary.
- Mark the location of the retaining wall: Use stakes and string to mark the location of the retaining wall.
- Excavate the area: Use a shovel or excavator to remove any grass, weeds, or other vegetation from the area where the retaining wall will be built. Excavate the area to a depth of at least 8 inches, or as required by your design.
- Install a base layer: Place a layer of crushed stone or gravel in the bottom of the excavation. Compact the base layer with a tamper or hand tamp.
- Install the retaining wall blocks: Begin at one end of the wall and place the first block in position. Use a level to ensure that the block is level and properly aligned. Continue placing blocks until the first course is complete. Use a rubber mallet to gently tap the blocks into place.
- Install the next course of blocks: Once the first course is complete, begin installing the second course of blocks. Place the blocks so that they overlap the joints of the blocks in the first course. This will help to create a secure, interlocking system. Continue placing blocks until the second course is complete.
- Ensure proper drainage: Drainage is an important consideration when installing a retaining wall because it helps to prevent water from accumulating behind the wall, which can cause the wall to become unstable or even collapse. Poor drainage can also lead to erosion or landslides.
- Backfill the wall: Once the retaining wall is complete, fill in the area behind the wall with soil. Tamp the soil gently to compact it and prevent settling.
Common Challenges to Consider During Retaining Wall Installation
Installing a retaining wall can be a challenging project that requires physical labor and attention to detail. It is important to carefully plan and execute the project to ensure that the retaining wall is safe and effective at retaining soil. Consider seeking the assistance of a professional if you are not comfortable tackling the project on your own.
Be careful when installing a retaining wall, this is an investment that will last for decades if properly installed. There are several common pitfalls that people often encounter when installing a retaining wall, including:
- Not considering the load: It is important to consider the load that the retaining wall will be subjected to, including the weight of the soil or rock that the wall will be holding back, as well as any additional loads such as the weight of vehicles or structures that might be placed on top of the wall. If the wall is not designed to withstand these loads, it can become unstable or even collapse.
- Not considering the soil conditions: The soil conditions at the site of the retaining wall can have a significant impact on the stability of the wall. It is important to consider the type of soil, the slope of the ground, and the water content of the soil when designing and installing a retaining wall.
- Not installing proper drainage: Poor drainage can cause a retaining wall to become unstable or even collapse. It is important to install proper drainage to prevent water from accumulating behind the wall.
- Not using the right materials: Different materials are better suited to different applications. It is important to choose the right materials for your retaining wall based on factors such as the load that the wall will be subjected to, the appearance you want to achieve, and the budget you have available.
- Not properly preparing the site: Proper site preparation is essential for the success of any retaining wall project. This includes clearing the site of debris, leveling the ground, and ensuring that the site is adequately drained.
- Not following building codes: It is important to follow all local building codes when installing a retaining wall. This includes obtaining the necessary permits and following all safety guidelines.
Retaining walls can be a significant project. A proper retaining wall install is a relatively complex piece of landscaping, we recommend working with professionals that understand the ask and can build something that will last.
The Advantages of Installing Retaining Walls in Your Landscape
- Supporting soil on slopes: Retaining walls can help to prevent soil erosion by holding back soil on slopes and preventing it from sliding or collapsing.
- Creating level areas: Retaining walls can be used to create level areas in areas where the land is sloped or uneven. This can be useful for creating a level patio or garden area.
- Controlling water flow: Retaining walls can help to redirect water flow and prevent erosion caused by water. This can be particularly important in areas prone to flooding or heavy rainfall.
- Enhancing the appearance of a property: Retaining walls can be used to create a visually appealing boundary or divide different areas of a property.
- Increasing property value: A well-built retaining wall can enhance the appearance of a property and increase its value.
Maximizing Hillside Stability and Restoration Techniques
Early we mentioned Hillside restoration, while retaining walls are a helpful piece of that puzzle there is much more that you can do for a hillside restoration project.
Hillside restoration is the process of restoring and stabilizing a hillside or slope to its natural condition or to functional use. Hillside restoration is important for a number of reasons, including:
- Erosion control: Hillside restoration can help to prevent erosion and landslides by stabilizing the soil and vegetation on the slope. This can protect homes, roads, and other infrastructure from damage caused by erosion.
- Water management: Hillside restoration can improve the water retention and infiltration capabilities of a slope, which can help to prevent erosion and flooding. It can also help to recharge groundwater and improve the overall health of the ecosystem.
- Habitat restoration: Hillside restoration can help to restore the natural habitat of a slope by planting native plants and creating a more diverse and sustainable ecosystem. This can provide benefits for wildlife and improve the overall health of the environment.
- Aesthetics: Hillside restoration can improve the appearance of a slope by creating a more natural and attractive landscape. It can also enhance the value and enjoyment of the surrounding property.
Overall, hillside restoration is an important practice that can help to protect and enhance the natural and built environment.
The root depth of plants can have a significant impact on the success of hillside restoration efforts. The root depth of a plant refers to the depth at which the roots of the plant grow and anchor into the soil.
In general, plants with deeper root systems are better suited for hillside restoration because they can provide better erosion control and stability. Deep roots can anchor the plant firmly in the soil, helping to prevent landslides and erosion. They can also help to hold the soil in place during storms and extreme weather conditions.
Plants with shallow root systems, on the other hand, may not provide as much stability and may be more prone to erosion. They may also be more susceptible to drought and other environmental stresses.
When selecting plants for hillside restoration, it is important to consider the root depth of the plants, as well as their other characteristics such as their growth habit, water needs, and suitability for the local climate and soil conditions. Using a mix of plants with different root depths can create a more diverse and resilient ecosystem.
It is important to have roots of various depths in a hillside restoration because a diverse root system can provide better stability and erosion control. Different root depths can help to anchor the soil and vegetation on the slope at different depths, creating a more resilient and sustainable ecosystem.
Having roots of various depths can also help to improve the overall health of the ecosystem by increasing the amount of water and nutrients that are available to the plants. Roots of different depths can access water and nutrients from different layers of the soil, which can help to reduce the impact of drought and other environmental stresses.
In addition, a diverse root system can provide habitat and food sources for a wide range of soil microbes and animals, which can further enhance the overall health and sustainability of the ecosystem.
Overall, having roots of various depths is an important factor to consider when designing and implementing a hillside restoration project. It can help to create a more diverse, stable, and sustainable ecosystem that can better withstand the challenges of the natural environment.
Ensuring Proper Drainage for Your Landscape
While drainage is an essential part of retaining walls, there are many other applications for drainage in landscaping.
A French drain is a type of drainage system that is used to remove excess water from an area. It consists of a sloped trench that is filled with gravel or other permeable material and is often used to alleviate problems with standing water or soil erosion.
French drains are helpful in a variety of situations, including:
- Removing excess water: French drains can help to remove excess water from an area by directing it away from the drain and into a natural water course or a drain field. This can help to prevent problems with standing water, which can damage foundations, cause erosion, and create a breeding ground for pests.
- Improving soil drainage: French drains can improve soil drainage by allowing water to percolate through the soil and gravel, rather than pooling on the surface. This can help to prevent soil erosion and improve the overall health of the soil.
- Protecting foundations: French drains can help to protect foundations from water damage by directing excess water away from the foundation and into the drain. This can help to prevent foundation cracking, settling, and other problems.
- Enhancing landscaping: French drains can be used to create attractive and functional landscaping features, such as dry creek beds or rain gardens. They can add visual interest and provide a natural way to manage excess water.
French drains can be a helpful and effective tool for managing excess water and improving soil drainage in a variety of situations and are commonly used in concert with a new retaining wall.
Let us know how we can help – reach out for a consultation!
From Our Clients

“This has been my favorite home improvement project. This company literally made me a yard where there previously was overgrowth, concrete, large stumps and rocks. They were able to complete the project on time and their cost was much more reasonable than others I interviewed. The project lead Fernando was hard working and communicative. The owner David (and Jeff previously) as well as the GM Chris all stayed in touch throughout the project. I would definitely use them for other projects in the future”

“The team put in an irrigation system in our front and back yard, cleaned everything up and added many new plants to the sunny and shady areas around our home. The owner was very personable, explained everything well and did exactly what he said he was going to do. He was fantastic to work with. His team was wonderful, super hard workers, and very friendly. They helped create color and beauty in every nook and cranny of our yard. My husband and I are very thankful we used this company.”

“Happy with my choice. I had a very small townhouse backyard that was a bit of a mess (low quality builder-grade plantings) and had somewhat of an idea what to do with it. They provided good advice and the final result turned out very well. Finished ahead of schedule too! One year later and I'm still happy with the result. I definitely won't forget the attention and responsiveness of this company. Thanks a bunch! ”