Q: I love the look of colored brick for paving, including my driveway, sidewalks and patio. 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: Fading concrete pavers are a problem that is so widespread, a service industry has sprouted up to do color restoration for pavers at homes and businesses.
Colored concrete paving brick took the home-building and remodeling industry by storm in the early 1980s. The first custom home I built had them specified for the driveway and front sidewalk.
The home I currently live in has colored concrete pavers. They make up my front and rear sidewalks. I didn’t build the house, and if I were intending to stay here, I’d rip them out and replace them with clay paving brick.
The reason that concrete brick pavers fade is simple. The manufacturers add dry-shake pigments in with the sand, small gravel, Portland cement and water that’s 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 ultrathin layer of colored icing.
In addition, all of the sand in the mortar used to join the pavers is coated with a cement paste that produces a solid monotone color. Look closely at old mortar and the color you’ll see is made up of the different colored grains of sand and the fine mortar paste between the sand.
The trouble starts early on, as both foot and vehicle traffic start to erode the colored cement paste, which is 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, the fine sand at the surface of the brick starts to erode from continued use. This wear is accelerated if you clean the concrete brick with a pressure washer. This is undoubtedly happening at the restaurant where you’re eating. They probably spray that outdoor brick after hours to keep it looking 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. The stones used in my pavers, for example, are very light, whereas the original brick color was a medium brown.
There are different oil- and water-based stains you can periodically apply to make concrete paving bricks 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.
A better alternative, in my opinion, is to use traditional clay paving bricks. They don’t change color, which 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 bricks are also durable. You can visit towns and cities all across the country where clay paving bricks have been used for their streets. In Athens, Ohio, for example, brick street surfaces that are well over 100 years old are in amazing condition.
Clay paving bricks can be installed by placing them on a compacted gravel base that has a bed of sand under the brick. Or use the method I prefer: Mortar the bricks to a steel-reinforced concrete slab so the bricks never move and you don’t track sand into the house.
Tim Carter has worked as a home-improvement professional for more than 30 years. To submit a question or to learn more, visit AsktheBuilder.com.