Trouble with concrete brick starts early on
Clay paving brick is a better choice to avoid color fading
Q: Tim, I have a big decision to make and need your help. I love the look of colored brick for paving, including my driveway, sidewalks and patio. The issue is I’ve started to pay attention to older installations of colored concrete paving brick and many look faded. Why is that happening? Some look horrible, especially at a restaurant I patronize. I don’t want my investment to look faded in a few years. Do I have alternatives, and is there a way to restore the color of faded concrete brick pavers?
A: These concerns are valid because fading concrete pavers are a problem all across the U.S. The problem is so widespread that a service industry has sprouted up to do color restoration for pavers at homes and businesses.
I clearly remember when colored concrete paving brick took the home-building and remodeling industry by storm. It was the early 1980s. The first custom home I built had them specified for the driveway and front sidewalk.
I recall having a conversation with the homeowner about them, and I went on record anticipating color fade as a problem, along with a second issue of moles that decided to tunnel in the sand under his pavers. I turned out to be right on both counts.
The current home I live in has colored concrete pavers. They make up my front and rear sidewalks. I didn’t build the house I currently live in, and if I were intending to stay here, I’d replace them with clay paving brick.
The reason concrete brick pavers fade is simple.
The manufacturers add dry-shake pigments to the sand, small gravel, Portland cement and water used to create the brick. This pigment has the consistency of flour and just like the Portland cement, it coats the surfaces of the sand and gravel. This is why new concrete paving brick has a deep color to it, as if each brick were coated with an ultra-thin layer of colored icing.
This same phenomenon is why homeowners complain after brick is tuckpointed with new mortar. The new mortar rarely matches the old mortar just inches away.
All of the sand in the new mortar is coated with the cement paste, which produces a solid monotone color. Look closely at old mortar and the color you see is made up of the different colored grains of sand and the fine mortar paste between the sand.
The trouble with colored concrete paving brick starts early on as both foot and vehicle traffic start to erode the colored cement paste that’s thinner than a sheet of paper. When this happens, you start to see the color of the different grains of sand in the brick. This is a subtle, slow process, and you rarely recognize it at first.
Next up, the fine sand at the surface of the brick starts to erode from more traffic. This wear is accelerated if you make the mistake and clean the concrete brick with a pressure washer. This is undoubtedly happening at the restaurant the reader eats at. They probably clean that outdoor brick each week after hours to clean off food spills and to simply keep it clean.
This high-pressure blast of water soon exposes larger pieces of stone and aggregate in the concrete brick. These stones can be quite different in color than the actual dry pigments used to color the brick. In my case, the stones used in my pavers are very light and almost white, whereas the original brick color was a medium brown.
There are different oiland water-based stains you can periodically apply to make the concrete paving brick look better. Clear wet-look sealers are also available. The clear sealers don’t do anything to mask the color of the exposed stone chips, but they do enrich the dry pigments in the cement paste between the sand and stone at the surface. Keep in mind that you have to apply these products on a routine basis if you want the brick to look their best.
The better alternative, in my opinion, is to use traditional clay paving brick. These bricks don’t change color, as the color is solid all the way through the brick. I’ve installed thousands of these bricks at my past homes, and they look as good 40 years later as the day I installed them.
Clay paving brick is also very durable. You can visit towns and cities all across the U.S. where clay paving brick has been used for city streets. In Athens, Ohio, for example, brick street surfaces well over 100 years old are in amazing condition.
You can install clay paving brick the same way you install concrete paving brick by setting them on a compacted gravel base that has a sand setting bed under the brick. Or you can use the method I prefer and mortar the bricks to a steel-reinforced concrete slab so the bricks never move and you don’t track sand into the house.