How to Build a Retaining Wall (and Why They Fail)

How to Build a Retaining Wall

Retaining walls fail for a number of reasons and I want you guys and gals out there that are installing retaining walls to learn a few tips and tricks of the trade that will help you improve your installation skill, and we'll separate you from the herd. What I am going to show you at the site today is a really common reason why a retaining wall falls apart. The first thing that we look at is the choice of blocks. A lot of times, landscapers will migrate towards the cheapest block and they tend to be hollow and have a lip on the back and neck. They're solid on the top and then they're hollow on the bottom, and what happens is that water can get trapped in there between the cavity and it has nowhere to go. Then it goes through a freeze-thaw cycle, expands, contracts and pushes the blocks over. They also have an inadequate pinning system. Because they're light, they're easy to pick up and they're fast to install. You see they have their connection method as this lip right here, this lip connects the block to the block below it, so let's look here, let's look behind this one.

Cheap Block

Having pins that you drive down and through the blocks, they just rely on a little tiny lip on the back of the block. They place the block on top and they simply slide it forward until this lip touches the back of the block. Once it touches, it's hands off and you're done, it's as simple as that. There are no pins, there's no mechanical connection method to keep this block from moving anywhere else other than the weight of the block itself. What happens is that block lifts as soon as it experiences a little bit of ground movement: a freeze-thaw cycle or maybe an earthquake or something else pushes it up. It pushes over and now there's nothing connecting it to the block below and that's where these blocks fail because they're hollow, remember, they're hollow on the bottom side. So they're lighter; I want you to see something here, this is what happens behind the blocks, look at that right there. I'm going to pan in a little bit. Blocks lift up because there are no mechanical methods to keep them held together. As the ground moves, the blocks which were perfectly fine before, now that lip isn't even holding anymore.

Drainage Issues

Another thing that they do, is they don't put enough drainage behind the retaining walls. So what happens is, instead of the wall being able to leak evenly behind and through the base of the wall, drainage gets trapped and hydro-static pressure builds up and blows out these retaining walls. Settlement, improper compaction, you can see how much the grade has dropped, it's a common occurrence and really it becomes evident when the grades settle behind the wall. So instead of being flush with the cap units, it drops down below the cap. You know, so the cap unit may be here, the grade is supposed to be here and allow the water to fall over the face of the wall. If this is the face, it falls down the face, but instead the grade settles and the water comes down, it goes behind the wall and so what happens is the wall is here, the water gets trapped and has the perk through it. If they don't have enough drainage aggregate it creates a belly. So all of a sudden, that wall gets fatter and fatter and fatter and pretty soon it just blows out and falls over.

Proper Compaction

Settlement, improper compaction, you can see how much the grade has dropped, it's jeopardizing this deck over here and the unfortunate truth is a lot of landscape companies use these same installation methods because it's fast, cheap, easy, and they can get on to the next one. This is also what I want, this is also the way I want you to separate yourself from those companies. I want you to explain what you're learning in this video to your customers, why retaining walls fail, how yours are different than everybody else's, what they will typically install and why you won't, why you will use a different type of block. My preferred block is a Versa-Lok standard unit, it's solid, it's pinned together, just has a lot of benefits and I explain that to my customers and I explain to them, what I will be bidding against when they get their comparative quote, I tell them nine times out of ten, this will be the block that they'll get.

Heavy Rains

Another thing is these retaining walls they don't slowly go, they pop like a balloon. I want you to imagine you are blowing up a balloon and you're blowing it up, getting bigger and bigger and bigger, then all of the sudden it just pops, it just ruptures and that's what happens when you have one heavy rainstorm. So as soon as you think a wall is in a state of failure, it's probably already been in the state of failure for weeks, months, maybe even years and it's only going to take one occurrence, one event, one heavy rain storm. It doesn't even have to be an unusual rain storm, any rain storm is going to create that. It's going to finish the retaining wall off, plain and simple, it's just going to be enough to push it over the edge. So I'm going to show you on this site, I hope that you guys can separate yourself from the rest, you can learn a little bit. Something that I like to do, is I like to, when I sell a job, I like to describe it that I'm going to use a solid block, so no water can get inside the core units themselves. I am also going to pin, I'm going to take two pins and physically drive them from one block into the next block below it. I'm also going to use twelve inches minimum of drainage aggregate behind the retaining wall and then I'm going to use a deep base of drainage aggregate as well.

Bid Apples to Apples

Use those simple principles, you describe the techniques, you tell what other companies will typically do, when you're bidding apples to apples. Another way I like you describe this is, like I tell my customers that when they're looking at comparative quotes make sure that the key components or the critical elements for a successful retaining wall are there: they're using a good block in the first place, they're using a good amount of base material underneath the wall and a deep, and a good amount of base drainage aggregate behind the retaining wall. When you do those things and you're able to describe those things with clarity and you're able to convey that level of quality that you intend to install on your products, your close rate is going to go up. So I want you to be able to differentiate yourself from your competition, learn what makes a retaining wall fail, learn how you can sell yourself on retaining walls.

What do you do differently?

What you do differently, this is the key element. Describe that process to your customers and they are going to go with you based on trust and integrity and the level of quality that they want to purchase; these are big decisions. When a customer is going to be doing a retaining wall like this behind me, they don't necessarily want to go the cheapest person out there, they want to go with someone that they trust, and is going to do a good job. You're the professional, you've got to understand your customers - they don't understand retaining walls. When you can break it down into its simplest components and deliver that message clearly and quickly to your customer, your close rate is going to show it, it's going to improve. So I love you guys, I hope this bit and this message helped, please hit the like button, that's a huge thing you know. Another great thing is if you could share for me. Tell other companies about what we're trying to do here, so we're all on the same page and you just benefit each and every one of us when we work together as a team. Love you guys, now go get back to work.


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