Proper Retaining Wall Drainage Prolongs the Life of the Wall

proper retaining wall drainage

Proper drainage prolongs the life of a retaining wall

A retaining wall is commonly used in landscaping to either make better use of a slope or create a decorative statement. Regardless of the reason why a retaining wall is used, it is typically constructed of a material such as brick, concrete, stone or wood timbers. Depending on its purpose, a retaining wall can be very short or very tall. With proper retaining wall drainage and construction, it can bring a lot of character and function to your landscaping.

Although retaining walls are a seemingly simple enhancement to any landscaping project, nearly 80% of all residential retaining walls fail at one point or another because of poor drainage. Even though it is often passed over, proper retaining wall drainage is the most important aspect of its structure. If water and soil find their way into the structure of your retaining wall, it can very quickly create a disastrous outcome, potentially destroying all of your hard work. For this reason, you should consult a professional very thoroughly before starting on any retaining wall project.

What are some of the things that you can do to ensure that your retaining walls have adequate drainage?

Proper Retaining Wall Drainage Tips

  • Use Backfill Properly – Whenever you hear the term “backfill,” it means the dirt that rests immediately behind your retaining wall. Rather than just filling in with garden soil, clay or any other material that you may have, it is very important that you use at least 12 inches clean crushed stone as backfill. Beyond this point, it is completely ok to use compacted soil from the area that you are doing the project in. If you have plans to landscape behind the wall, use at least six inches of native soil over the gravel backfill.
  • Lay Perforated Piping In addition to the foot of backfill that is used behind your retaining wall, you should also make sure that perforated piping is laid at the bottom of the backfilled portion of the wall. This helps to create a hollow channel for water to go in the event of a heavy rain or watering. This piping can then be used to divert the water away from your retaining wall so that you do not have to worry about it collecting behind the wall, causing pressure and decay.
  • Install Weep Holes – Another important aspect of your retaining wall drainage plan is to have properly installed weep holes. Work with your landscaping expert to ensure that these holes are appropriately placed and sized to ensure that any excess water can drain through the wall. This will essentially give any moisture an additional route away from your wall, which is your ultimate goal.

It goes without saying that you will want to do everything in your power to protect the substantial time and money that goes into creating a retaining wall on your property. Because of this, make sure that you’re not making one of the most common (and most destructive) mistakes that any homeowner can make: bypassing proper retaining wall drainage to save money. By spending a little bit of extra time and a few more dollars at the very beginning to ensure that your wall drains properly, you can be sure that it will remain in place for many years to come.

Posted in Drainage, Landscape Construction, Retaining Walls.


  1. I am glad that you brought up weep holes. I have been thinking about installing a timber retaining wall in my backyard this spring. But I haven’t thought at all about how rainwater will travel throw the wall. It seems like I should talk to a landscaper about how best to do that for the type of wall I want.

  2. I’d love to get a retaining wall installed in my backyard, so it’s helpful to know that proper water drainage is essential for its longevity. It was helpful that you suggest using at least a foot of crushed stone as backfill when constructing the wall. Is this something I can count on being done if I leave the job to a contractor that specializes in stormwater drainage?

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