Retaining Walls

A: Retaining walls are hardscape elements that add structure and beauty to the landscape. Obviously, it needs to be designed appropriately; however, when it’s done right, it will add a beautiful layer of design to the landscape.

If there are slopes in the backyard, retaining walls help level the area, hold soil back, prevent erosion, and manage slopes. Walls break up the continuity of a sloped backyard. For example, if you have a 3 ft elevation change with the house being lower, a 3 ft wall will serve as the retaining system for all the soil. It will give the area structure and provide a focal point in the backyard.

When there is a slope, water accelerates, flowing through the landscape, dissolving soil and causing erosion.

A sloped backyard also has the least amount of level area for play, so the wall reduces the elevation change to a minimum and removes the ramp-like feel in the backyard.

A similar scenario is when the house is at a high level with a 3-foot drop to a lower area. By putting a wall at the end of the property line and filling up the drop with soil, homeowners gain all that usable space.

A: Homeowners have many options to finish or veneer a wall, but there are limited materials for the foundation and retaining system.

Modular blocks, concrete-molded to a rectangular shape, build the wall at the best value. These segmental concrete walls sit on a gravel or aggregate foundation and are stacked to the desired height. Manufacturers can beautify these by adding dye to the concrete and creating different sizes and textures. The price per square foot depends on the concrete’s quality and texture, while labor costs often remain the same.

Another method is creating a full-on concrete foundation and retaining wall. The foundation must be all concrete, and the wall must become a unit with the foundation, using rebar. The wall could be made with cinder block or framed and poured concrete.

Simply put, at this stage, the walls are done and performing their job: retaining soil and preventing erosion. But homeowners often go further and face these concrete walls with a decorative finish using natural stone, faux stone, or outdoor tile.

We don’t recommend wooden retaining walls. Pressure-treated lumber does not last long when it actually comes into contact with soil. They usually rot in 5 years or less and require a redo. We still see timber walls that last 30 to 40 years, but the EPA has changed their formula for outdoor treatment.

A: Depending on height and distance from the house, the wall can host some fun activities or accessories.

• For kids, they become a jumping rock when their height is less than 3 ft.
• Depending on height, it can also serve as a soccer practice wall.
• For ambiance, we recommend putting under-cap lights to illuminate it at night.
• The wall becomes an amazing feature.

Outdoor Makeover and Living Spaces have also turned walls into water features. With the elevation change of a wall, we’ve designed water spillways or actual waterfalls using boulders to guide the water down.

A: Most walls under 3 ft are simple, as long as the right-size foundation and a proper drainage system have been built to alleviate the buildup of hydrostatic pressure. So most cities and codes are more relaxed because they don’t require permits for these short walls.

However, many cities and municipalities still require a soil disturbance permit for grading and moving dirt around to create a wall. It is best to check with the city.

For walls above 3 ft, other geological factors begin to affect the wall and push it. This is where the city requires a permit to ensure it’s built properly. Our team is in touch with engineers to gather feedback and build it to spec, meeting and exceeding city requirements, and rendering the wall with the longest longevity.

A: Outdoor Makeover and Living Spaces has rebuilt many new walls. We know it’s convenient to hire the lawn guy; they’re already there, you have a relationship with them, and they’re always nice and pleasant. They are often the first choice to redo things outdoors.

But as we expect great results in other aspects of our lives, walls have to be built to a certain spec to stand and last a long time. We see uneven rows in walls, clay leeches between the blocks, unglued caps, and bowing—all common issues.

There’s only one way to build walls properly, and NCMA (National Concrete Masonry Association) provides that training. We are proud to say that we all follow NCMA as our standard operating procedure to ensure all of our walls meet code.

A: Yes, they are. Stacked stone walls are masonry walls that require a concrete foundation and concrete block to retain the soil. Once you have the wall to this point, it takes days to face the concrete wall with intricate stonework. It takes a lot of precision and craft to create stacked stone walls. All of these factors add complexity—hence the extra labor and cost.

A: As designers, we all prefer the terraced look. We could build a 6 ft wall or two 3 ft walls about 4 ft apart, which creates a softer hardscape. The space between is often landscaped with beautiful plantings, which soften the second wall.

Standing next to a tall wall makes the space feel smaller, whereas two walls open it up. The only time we’d go for a large wall is when space is limited.

A: Yes, if you truly must—or can’t afford a wall project.

Usually, there’s a lot of work involved in bringing in enough soil to the backyard to support a drop-off. The soil slope has to meet a 3:1 ratio to hold the dirt behind it—that’s 1 ft of elevation for every 3 ft of slope (33 degrees). This is the slope geotech engineers recommend. It must be compacted and cannot have flowing water on top, as that causes erosion.

Although this is necessary in certain applications, in a homeowner’s backyard, this would eat up so much usable space. Retaining walls solve that problem—even though they are incrementally more expensive.