Install Proper Drainage Aggregate

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Retaining Walls - How to Avoid Costly Mistakes and DIY your landscaping Walls with Great results!

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What happens here

Ensure adequate drainage aggregate is installed behind the retaining wall. The industry standard recommends at least 12 inches of drainage aggregate behind the wall, but increasing this to 18 inches or more provides superior long-term stability and is considered 'cheap insurance' against failure. Many contractors neglect this, using insufficient or no drainage aggregate, or installing drain tile incorrectly (e.g., at the top of the wall without aggregate). Proper drainage aggregate, typically 3/4 inch clean rock, should be placed behind the wall and ideally connect to a storm sewer system or virgin soil to effectively manage water.

Goal: Ensure robust drainage behind the retaining wall to prevent hydrostatic pressure buildup.

Tools and materials

Mini Excavator — Excavating and moving soil, and assisting with the placement of drainage materials
Shovel — Manually placing and adjusting drainage aggregate
Skid-steer Loader — Transporting and placing drainage aggregate and other backfill materials efficiently
Drainage Aggregate — Allowing water to drain freely from behind the wall, reducing hydrostatic pressure

What they say

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critical to the long-term success of your retaining wall. But even more critical is getting the right amount of drainage aggregate. Now, the industry standard is to put 12 in behind the retaining wall. But I'm going to tell you to deepen that to 18 even more in just cheap insurance. Is going to ensure you long-term success. Let's This is a new one. Tim and I have never usually seen the drain tile installed at the top of the retaining loft without any drainage aggregate. Exactly. We found one row of geogrid placed in this wall. Right where we found the geog grid was the only place on this site the wall still seemed to be intact. That's how important it is to get the geo grid right. When you're designing a retaining wall, you have to take into consideration the kind of soil that you're going to be working with and the load directly behind and above the retaining wall. So, some of the basic changes you're going to see us make today on this retaining wall is we're going to build one wall. We're not going to build a terrace wall. We're also going to engineer this wall and fortify it with geog grid. We're going to accommodate for the load that the driveway places on it. The driveway places a search charge onto the retaining wall. So, we install extra geog grid to compensate for that. It's time to go to West Virginia where we bust myth number two. One of the myths is when you see a retaining wall collapse, you don't see the drainage aggregate. The drainage aggregate actually is one of the first things that usually gets washed away. If the drainage aggregate is going to be on this site, it should be in this virgin soil. So, when I come into a site like this, I look for the drainage aggregate at the bottom of the retaining wall in the storm sewer system or in the virgin soil behind the retaining wall. If we're going to find it, this is where we're going to find it. And we got nothing. And that's the problem. Most companies are either going to use the wrong drainage aggregate or worse yet, none at all. Is this the footing material they

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