To Etch or Not to Etch: What Do Concrete Contractors Recommend?

The lifespan of a coating or overlay party depends on its adhesion to the concrete surface. If it does not adhere properly, it will flake and chip off. Although it is common to blame the coating for being low-quality, it is actually the concrete that failed. Concrete may contain laitance or contaminants that hinder a coating from supposedly sticking on the surface. This is why it is important to prepare the surface well prior to resurfacing. Professional concrete contractors know that surface preparation phase is the most crucial parts of the job. One way to make the concrete ready is by acid etching.

What is Acid Etching?

Acid etching is the process of neutralizing a concrete surface through the use of muriatic or phosphoric acid. The acid is applied on the concrete and then rinsed off with water. This has been the standard method for preparing the concrete slab for a coating or overlay. However, the debate on whether it is still acceptable to do is confusing homeowners. Should it be done or not?

Advantages of Acid Etching

• Acid etching is used to extrude and fabricate concrete
• It is effective in reducing the color variation, creating a more uniform color
• Etching can be used to smoothen out a concrete surface
• It opens the pores of a concrete slab, enhancing adhesion
• Less labor-intensive method than grinding or sandblasting

Disadvantages of Acid Etching

• Results are inconsistent since not all concretes are the same
• It can damage the concrete slab when it is over-etched or under-etched
• Since an acid is used, it is dangerous for both humans and the environment
• It adds unnecessary costs to a project and affects the time frame of the project

Safer Alternatives to Acid Etching

There are safer alternatives to acid etching today. Most concrete contractors are no longer recommending acid etching because of its effect on health and the environment. Instead of etching, sandblasting or grinding is a great way to remove any contaminants on the surface of the concrete slab and to open its pores as well.

If you should have concrete work done in your property, make sure to choose a contractor who uses a safer yet effective surface preparation method. It is important to ask them how they plan to prepare the surface. If they mention acid etching, ask if they could use an alternative method instead. Better yet, find another concrete contractor to work with.