How to Build a Retaining wall (and why they Fail)
What you're going to learn today is one of the most common reasons for why retaining wall falls apart.
Retaining walls fail for any number of reasons and I want you guys and gals out there, that are installing retaining walls, to learn a few tips and tricks to the trade that will help you improve your installation skills, so you can begin separating yourselves from the average landscaper.
The first thing that we inspect is the choice of blocks. With so many people willing to cut corners, it's no surprise that some "landscapers" will migrate towards the cheapest block. These blocks are hollow with a lip on the back. They're solid on the top and then they're hollow on the bottom, and what happens is water can get trapped in there, between the cavity, and it has nowhere to go. It will eventually, go through the freeze-thaw cylce, expanding and contracting until the blocks are pushed over.
Instead of having pins that you drive down and through the blocks they just rely on a little tiny lip on the back of the block to place the block on top and then 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 lift as soon as it experiences a little bit of ground movement, freeze-thaw cycle or maybe an earthquake or something else, it pushes 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 right there, the blocks lift up and because theres no mechanical method as the ground moves - the blocks, which are right there perfectly fine are forced up and over. Now just that lip isnt even holding them anymore.
Another thing that they do, is they don't put enough drainage aggregate in behind the retaining wall. As a result, instead of the the wall being able to eat evenly behind through the base of the wall it gets trapped and it has a hydrostatic pressure builds up and blows out these retaining walls.
Settlement, improper compaction, you can see how much the grade has dropped.
Its a common occurrence and really it becomes evident when the grades settle behind the wall - so instead of being flush with the cap units and drops down below the cap unit: 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. But instead it has to settle and the water comes down and goes behind the wall, so what happens is the wall is here, the water gets trapped and has to perk through it and if they don't have enough drainage aggregate it creates a belly.So, all the sudden that wall gets fatter and fatter and fatter and pretty soon blows out and falls over.
The unfortunate truth is a lot of landscape companies use these same installation methods because its fast, cheap, easy and they can get on to the next one.
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, 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 lock standard unit. Its solid, its pinned together, it just has a lot of benefits and explain that to my customers and explain to them what I will be bidding against.When they get their comparative quotes, I tell them nine times out of ten this will be the block that they'll get.
Another thing is these retaining walls and they dont slowly go, they pop like a balloon. I want you to imagine you're blowing up a balloon and blowing it up getting bigger and bigger and bigger than all the sudden it just pops, it just ruptures. That's what happens when you get one heavy rainstorm. Just when you think the wall is in a state of failure, it's probably already been in a state of failure for weeks, months, maybe even years and it's only going to take one occurrence; one event; one heavy rain storm is going to be the event, it doesn't even have be an unusual rainstorm. Any rain storm. Its gonna finish the retaining wall, plain and simple. It's going to be enough to push it over the edge.
I hope that you guys will use this information and begin to separate yourself from the rest. You can learn a little bit something. Whenever I'm selling a job I like to describe it as I'm going to use a solid block, so no water can get inside the core units themselves.
I'm also going to take two pins and physically drive them from one block into the next block below it. I'm also going to use 12 inches, minimum, of drainage aggregate behind the retaining wall, and then I'm going to use a deep base of drainage aggregate as well. Use those simple principles, you describe the techniques, you tell what other companies will typically do so when you're bidding apples the apples - another way I like to describe this: is like to tell my customers that when they're looking at comparative quotes make sure that they key on components which the critical elements to successful retaining wall.
The Key Elements to a Successful Retaining Wall
1. Solid Blocks
2. Mechanical connection
3. 12" Drainage aggregate
4. Deep Base Material
They're using a good block in the first place. they're using a good amount of base material underneath the wall 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 and tend to install on your project.
Your close rate is going to go up.
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 you do differently.
Describe that process to your customers and they are going to to go with you based on trust and integrity in 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 for the cheapest personnel. They want to go with someone that they trust 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 simple-ist components and can deliver that message clearly and quickly to your customer, you're close rate is going to show. Its going to improve.