Retaining Walls 101

Make no mistake about it, a retaining wall is a significant investment of time and money. The key term here is “investment,” because when it is done correctly, it can provide enjoyment for many years. Like any big project, it is best to know something about it before you start talking to (and paying) landscaping professionals.

Retaining Walls Should Match Your Lifestyle
Often, retaining walls are merely seen as a way to hold back soil. Get past that mindset. Well-planned retaining walls should work with your yard and help create an aesthetically pleasing environment that can be used for more than just holding back soil.

Don’t Be Afraid to Get Creative
Nothing in your yard is perfecting straight. Trees don’t grow straight up. Flowers lean as they wish. The shape of your yard likely has contours.

So, don’t assume that your retaining wall has to be perfecting straight. Adding curves and contours are a creative way to please the eye and have your retaining wall work with your yard instead of next to your yard.

Size Absolutely Matters
If you are looking at a relatively short retaining wall (e.g., less than four feet tall), the planning is pretty straightforward. As you start to get larger than that, though, it can get tricky. First, you will need to know what local codes apply to such structures. A good landscaper will already know, which is one reason to go with a professional. Another reason is that the collective weight of materials on larger walls often means some unique engineering may be involved.

Keep Terracing in Mind
As mentioned, taller retaining walls carry certain concerns.

For instance, at a lower grade, you will need to incrementally step up the retaining wall to attain a greater slope. This will need to be done gradually, with an eye for a slight offset at each course change.

Consider Your Materials
There are a number of different retaining wall options.

Manufactured blocks and stones, when used in retaining walls, tend to offer a more consistent appearance. They can also provide improved structural integrity with less planning. Because they are manufactured, installation is pretty straightforward in terms of ensuring that each course remains level.

This can save a tremendous amount of time installation versus boulders.

Pro Tip: Blocks and stones will often have slight variations in color. Try to match them the best you can and keep the stones that match the least at opposite ends of the wall.

Build a Solid Foundation
A solid foundation starts at the base.

Dig your base a few inches below grade, then tamp it down to make sure it is level. Again: make sure it is level. If you will be adding gravel or any other type of filler, it needs to go down at the foundation before the first stones, blocks, or boulders are set in place. The importance of the base being level cannot be stressed enough. If it is off even a little at the base, the difference can be exacerbated with each additional layer of the retaining wall.

Adding the Drain Pipe
If your retaining wall is going to have a slope dropping, you will need to incorporate drainage at the base of the wall. Place gravel at the base and implement a fabric-covered drainage pipe. The fabric helps to ensure the drainage pipe doesn’t clog. This is pretty important, because the only way to unclog it later is to dig the whole pipe out. Trust us, you don’t want to be in that situation.

Keep it on the Level
Not to sound like a broken record, but you have to keep it level. As we mentioned in the section on the foundation, any course of stones that becomes un-level will only cause more problems farther up the wall. To keep the wall strong, sturdy, and balanced, take the time to ensure that each course is level before starting on the next course.

Adding Support with Backfill
Backfilling should occur as new courses are added, not when the wall is completed. When you backfill as you go, it creates much greater support for the wall layer after layer. To avoid backfill settling over time, you’ll want to be sure the backfill is tamped down with each new course layer.

Top it All Off
Cap blocks along the top of a retaining wall are a really nice finishing touch, similar to the edging on a paver patio They can be easily held in place via masonry adhesive.

In Conclusion
At E.P.M., we want our customers to be knowledgeable of what is happening at every step of a project, especially at the beginning. That’s why our landscape design professionals discuss not only design with you, but also the logistics of carrying out that design. You work hard for your money and you deserve to know how it’s being spent, especially on a project with the scope of a retaining wall. If you are considering adding a retaining wall to your landscaping, we encourage you to contact us today or give us a call at (517) 990-0110.