5 Reasons Not to Retemper the Concrete Surface with Water

Hot, dry, windy conditions are known for drying out the surface layer of freshly placed concrete. This early dehydration of the concrete surface results in crusting, cracking, and crazing.? Not only can these problems raise concerns about the durability of the concrete, but they are also an eye sore and can impact the final appearance of stamped concrete. That’s why keeping the surface of the concrete moist and workable is super important. For many years, it has been the recommendation to just apply a thin layer of water to the concrete before troweling. Unfortunately, tempering the concrete with water presents additional challenges and risks to the finished product.?

What Are the Risks of Retempering the Concrete with Water?

Working with concrete requires a lot of patience and precision, especially when adding additional water or materials to the process. Here are some of the main concerns associated with retempering the surface with water.

Overhydration and Weakening of Concrete: Spraying too much water on concrete can lead to overhydration, which dilutes the cement paste. This can significantly reduce the strength and durability of the concrete. When the water-cement ratio is excessively high, the concrete becomes porous and less dense, making it more susceptible to damage and deterioration over time.

Surface Scaling and Dusting: Excessive water application can cause the surface layer of the concrete to weaken, leading to scaling and dusting. Scaling is the flaking or peeling away of the surface layer, which can result from the freeze-thaw cycles in cold climates. Dusting, on the other hand, occurs when the surface produces a fine powder residue due to a weak cement paste. Both issues not only affect the aesthetics of the concrete but also its functional integrity.

Formation of Weak Surface Layers: Spraying water can sometimes create a weak, overly smooth surface layer known as laitance. This layer consists of fine particles of cement and aggregate that rise to the top when too much water is present. Laitance lacks the strength and durability of properly cured concrete and can be easily worn away, exposing the underlying, stronger layers to damage.

Uneven Moisture Distribution: Improper water application can lead to uneven moisture distribution, causing differential drying and potential internal stresses within the concrete slab. This uneven drying can result in warping, curling, or even cracking as different sections of the concrete expand and contract at varying rates.

Increased Risk of Shrinkage Cracks: While spraying water can prevent surface cracks, it can paradoxically increase the risk of shrinkage cracks if not done correctly. When the surface remains overly wet while the underlying layers dry and shrink, it creates a tension that can cause the concrete to crack internally.

What is the Alternative to Retempering with Water?

While it may be possible to retemper the surface with water, making sure you’re not using too much water can be very, very difficult.? That’s why the best way to prevent damage to the concrete surface is to use a finishing product, such as Fritz-Pak’s Control Finish.

Control Finish is a chemical finishing aid that is designed to help the concrete surface maintain its moisture on even the hottest, driest days at the job site.? You simply mix the material in a sprayer, apply a thin layer to the concrete, and then work the product into the concrete. It is just as simple as applying water, without the additional risk.? You can also use products such as an evaporation retarder or a densifier to further improve the finishiability of your concrete.? Check out the video below to learn more.

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If you’re ready to improve your concrete’s finish, go online to fritzpak.com to order your case of Control Finish today.? Don’t forget to follow our social media channels for more information about how our products can improve your concrete.