"Taking on Water" – A Stamped Concrete Patio
The final step of a stamped concrete overlay project is to apply a sealer. Not only does a sealer enrich the color of the stain applied to the stamped overlay, but a sealer also protects the concrete from normal wear and tear.
This prevents damage from outside sources such as water stains, tire marks, leaf stains, or chemical stains. With the help of a sealer, a concrete surface can sustain a pristine condition and look like new for years.
This should have been the case at this Prosper, TX home, but instead, the sealer we applied did something unexpected. The homeowner had contracted us to place a stamped concrete overlay on the patio. After laying down the stamped overlay, we applied a sealer on top of the new concrete, packed up, and went home.
Usually, that would have been the end of it. Months later, we got a call from the homeowner, who’d found a problem. The sealer should have stayed clear, but instead, it had turned white.
This had never happened before, and we couldn’t understand why the sealer had failed. We agreed to return home and take a look at it. As normal, before resealing the stamped concrete patio, we used a power washer to clean the surface of any dirt and stains.
We noticed that the water from the power wash would sit on top of the concrete overlay instead of draining to the lawn as it is supposed to do. We immediately realized what was happening.
In the months after we’d done the stamped concrete patio, the homeowner had added a patio extension. Normally, concrete patio extensions are sloped so that rainwater drains toward the lawn. In this case, the extension was sloped but in the opposite direction; it would drain toward the house and the stamped concrete patio.
Rainwater would pool on the stamped concrete overlay, sometimes for days before it would eventually evaporate.
Our sealers are tough, but they aren’t designed to be constantly immersed in water; that was why the sealer failed.
The homeowner called the contractors who’d built the patio extension, and they installed a drain. This solved the problem, and we were able to apply a new sealer over the stamped concrete patio. This time, the sealer worked and remained clear.
In any circumstance, damage to the sealer can lead to damage to the concrete underneath. It is important to clean your concrete surface on a regular basis. We recommend using a neutral base cleaner.
Unlike cleaners that contain vinegar, bleach, or ammonia—which are aggressive enough to strip wax and can damage the sealer—a neutral base cleaner causes no harm. On outdoor concrete surfaces, use a garden hose or pressure washer to rinse off dirt and debris.
You can use a leaf blower to force dry the concrete for a streak free finish or just let it dry naturally.
We suggest treating your concrete surface the same way you’d treat a hardwood floor. Heavy items dragged across the concrete can cut through or scratch the sealer.
Alternately, if you have something that frequently rolls around in the same area it can also damage the floor; dirt stuck in the wheels can be ground into the floor and penetrate the sealer.
To solve this problem, we recommend using a hard surface mat or equivalent or switch to softer rubber wheels. Avoid any mats or underpad with a rubber backing. The rubber can stick to the sealer and it can also trap moisture between it and the concrete; over time, the trapped moisture can turn the sealer white, much like what had happened to our stamped concrete patio in Prosper.
Placing tape on the concrete is also a bad idea; we’ve seen tape pull off sealer, stain, and, if it is particularly aggressive, say duct tape, even the top layer of concrete.
Sometimes, accidents happen. Light scratches and stains can typically be fixed with a fresh coat sealer after a good cleaning.
Chips can typically be blended in using a wood stain marker that is similar to the color of the floor. If the chip is very large, bigger than a quarter, contact us, and we can apply a patch to the area.
When properly cleaned and maintained, sealers on outdoor surfaces like a stamped concrete patio will last for two to four years before they need to be reapplied.
If the surface color changes dramatically when it gets wet and has a chalky appearance when dried, that’s when it’s time to reseal.
