Permeable Pavers vs. Base Systems

I’ve owned a hardscaping company for more than 3 decades and have been coaching fellow landscaping and hardscaping businesses for over 2 decades, so as you can imagine, I frequently field questions about basic hardscape install techniques from companies and manufacturers in our industry.

I believe that, from time to time, such industry-specific content will be highly valuable to the Rooted Leadership audience as well. So consider this the first of a new category of posts: nuts-and-bolts insights and tips about landscaping and hardscaping. 

Permeable Base Systems

Here’s a question a fellow contractor recently asked me: “How do you feel about using a permeable base system in residential applications, with standard pavers and a polymeric jointing sand?” 

Answer: the concept has some merit, but I am not sold on it. 

And associations like the Concrete Masonry and Hardscape Association (CMHA) are not advocates of it at this point either—which is important to take into account, considering that they draw on the knowledge of hundreds of professionals in the industry and base their best practices on techniques that have been proven in the field. While open to new techniques or materials, the CMHA will research and evaluate thoroughly before adopting them as a best practice. 

All to say: such organizations are great resources, so it’s wise to take their recommendations into consideration!

Standard Paver Application Over Well Compacted Subgrade

A standard paver application over a well compacted subgrade will stand the test of time. 

If the fear is that water is the culprit for the many paver failures we see, I would contest that claim. More likely, the following are the actual issues:

• Poor preparation of the subgrade
• Improper aggregate base material
• Incorrect use of bedding sand 
• Inability to achieve maximum proctor density with the compaction equipment used during installation

(Many contractors do not possess a compactor that delivers the necessary pounds of centrifugal force, which makes it very difficult to achieve proper density.) 

Add the factors up, and the results will eventually equate to paver failure.

So how does the use of an aggregate base without fines help alleviate these problems? 

Will you compact the subgrade or not? 

How will you know if you have achieved density with a clean aggregate? 

How will you move the water that does enter into the system? Water will find the path of least resistance, and if you don’t find a way for it to exit the system, it will cause you bigger problems, such as a saturated subgrade, which will cause paver failure. 

How will you maintain the integrity of the polymeric jointing sand over time, especially if it is under a load of any sort, such as tire traffic? When the polymeric sand breaks down, which it will, it will not choke off properly into the chip stone. Instead, it will get lost into it, potentially setting you up for another failure: paver deformation.

In other words, the quality of your installation is the key to the hardscape’s long-term success.

Experienced Planning & Quality Execution

While we are all working hard to find the next best trend, if we cut corners or jump into a new methodology quickly, we’re in danger of giving our industry a black-eye. Our ultimate goal should be to raise the quality standards of the landscaping and hardscaping industries! 

Truth:

When people see pavers that have failed, they rarely think, “It must have been an inept contractor who didn’t do the critical work correctly.” 

Instead, most likely, their first thought is, “I don’t want those pavers in my yard,” then, “I thought I wanted them, but look what happens when you work with them,” followed lastly (and most damagingly) with, “I’ll just have a deck installed, or exposed aggregate concrete.” 

It’s safe to say that this is the last thing any of us hardscapers want to see happen.

Permeable paver installations are important and widely needed in both residential and commercial arenas. And they work very well when installed using proven permeable paver installation methodologies from start to finish. 

Let’s not try a hybrid of standard and permeable systems—at least until the day when an entity like the CMHA has put a stamp of approval on the approach.

Keep up the quality work! 

Pitter patter, let’s get at ‘er.

Matt!