New products are constantly being introduced by the home improvement industry. If you’ve been around long enough, you can spot ones that have lots of sizzle but most likely won’t stand the test of time. I had that feeling 40 years ago when I first saw colored concrete paving bricks.
It turns out my gut feeling was correct. The evidence is all around you that concrete paving brick can’t lace the boots of true clay paving brick. Here are just a few of the reasons.
You might have a patio paved with concrete bricks, or you might walk on them at a park or outdoor shopping mall. These pavers come in many shapes, sizes and colors. Several years ago, my wife wanted an instant outdoor patio, and I could only satisfy her desire by using large-format concrete patio stones that came in different sizes. They interlocked in a random ashlar pattern.
The large pavers I used were made the same way as the concrete brick you may have. Concrete companies mix small stone chips, coarse sand, Portland cement and dry pigments together with a precise amount of water. The mix is poured into molds to make the brick or larger pavers. They’re cured to gain maximum strength, and the colors are rich when the products leave the manufacturing plant. The color you see is created by the ultra-thin pigmented cement paste covering the sand and gravel at the surface.
By contrast, real bricks are made from clay. The clay is cut into the final brick shapes and then fired in a huge kiln. The high-temperature firing process produces a chemical change in the clay, creating an artificial rock of sorts. Some clay bricks can be fired so hard they are strong enough to be used as normal street paving.
Clay paving bricks don’t change color over time. Concrete paving bricks fade and change color. The thin-colored cement paste in concrete pavers wears off with normal wear and tear; you can blast it off using your power washer. After one or two cleanings, the color of the stone chips and sand starts to dominate the surface appearance.
Another issue with concrete paving bricks is the way they’re set. Almost all are set in a bed of sand. Burrowing animals can and do tunnel through the sand. The bricks can settle and tilt, and they look horrible in short order. I know this because it happened at my own home. I didn’t build the house I live in, and I inherited two walkways made of concrete paving brick when I bought this home. One walkway looks better than the other, but both no longer are as flat as they were when installed.
Weeds and concrete paving bricks are like peanut butter and jelly. You can count on weeds growing up in between the bricks if you live where you get enough water to support the growth. A weed hacker can be used to trim the visible growth, but days later the weeds sprout new green growth.
Ants love concrete paving brick. They transport the sand underneath the brick up to the surface as they create comfy nests. You can broom or blow the sand away with little effort, but it’s just another nuisance to deal with.
The gaps between concrete paving bricks are typically filled with fine sand. Some pavers have tiny bumps on the sides so a wider joint between each brick is created once installed. My large-format pavers had this.
Manufacturers have known for decades that people love to clean their concrete pavers with a power washer. The issue is no matter how careful you are, the high-pressure stream digs out the sand.
The manufacturers responded by inventing polymeric sand. This is just sand that comes with a water-activated adhesive. When I first saw this product, I was skeptical. I simply couldn’t believe that a water-based adhesive could withstand Mother Nature. Once again, my gut instinct was spot on.
I used polymeric sand between the pavers of the patio I built for She Who Must Be Obeyed, knowing that it was doomed to fail. I followed the instructions to the letter, and the sand looked fantastic for two years. Then it slowly succumbed to the harsh New Hampshire winters. I have weeds growing on my patio, some of the sand is missing, and it all needs to be redone.
If you want a trouble-free brick patio, my suggestion is to do what I’m starting to do at my son’s house. We’re installing thin split clay paving brick on a steel-reinforced concrete slab. The space in between each brick will be filled with mortar that will test out at 12,000 pounds per square inch. Soon, you’ll read an upcoming column about this project, and I’ll share detailed step-by-step videos of the process.
