How to Correct Acid Stain Colors on Concrete

Question

I put a textured concrete overlay on my concrete floors. I did all the cleaning processes, and I applied acid stain in buff, cola and amber colors. My problem is that I wanted more of a yellow tone, and instead, it is more orange with some yellow! I have tried sanding some of the orange off and it has lightened it, but not enough. I am a DIY person and have never tried this in my life. What can I do now to fix this? Can you give me some insight on how to correct acid stain? What are my options?

A DIYer used a mild acid solution to remove some orange from this acid-stained floor, then added darker colors. Photos courtesy of Candace Reese
Answer

While I advocate hiring professional decorative concrete installers for projects, I also realize that there is a large segment of the decorative stain market that is made up of weekend warriors and DIYers. Even after more than 20 years of industry education on staining, I get as many questions like this from do-it-yourselfers as I do from people who hired a professional installer.

Stain remains a popular finish, and while the number of problems or complaints has decreased over the last few decades, the problems remain the same, and they don’t discriminate between professionals and DIY homeowners.

Because of this, I begin my response to most of these types of questions by saying, “Welcome to the world of acid staining!” You should expect variations in color.

A sample area would have saved a lot of time and heartache. This is a classic example of why the industry preaches samples. Making a mock-up or small sample of the different colors on the floor would have shown that certain stain colors were creating an orange color and not the yellow or light brown the homeowner wanted. Unfortunately, that is water under the bridge. The good news is that a sealer had not yet been applied, which saved the major headache of having to strip the floor before doing any color correction.

At this stage in the project there are a few options

You can use a mild acid to remove some of the color. A solution of 40 parts water to 1 part muriatic acid, a scrub brush and cotton rags will help remove the stain.

Keep in mind that acid stains are not soluble in water. This means that water alone will not do much in regard to removing the orange-colored stain. A small amount of acid added to the water will pull the stain out of the concrete without etching the concrete surface.

In essence, the acidic solution reverses the reaction, allowing you to pull the color back out of the concrete. You can let the surface dry and then work back into the floor with the stains to get the desired color. This method is by far the most successful when wanting to pull stain back out of concrete.

You can work other acid stains (or most any kind of stain) into the floor to try to get the desired color. You may get what you want or you may not. This works best when you want to go from light to dark colors. I would not try it if you are going from dark to light, as in this case.

Concrete Decor Correcting Acid Stain Colors on floors. Made a mistake while coloring your concrete and used darker concrete stains to correct the problem.

Another satisfied customer

You can apply a dark stain in just certain areas to try to produce highlights to offset the orange. This is more of an artistic approach, and having a comfort level with how stains react and produce colors on concrete is recommended.

You can apply a tinted sealer over the stain to try and hide the orange. This is the cheapest option and produces a Band-Aid fix. When you use this method, the repair color is tied up in the sealer, so if the sealer wears so does the color.

Whatever method you decide to use, test in a small area until you get the desired results! In this case the homeowner/installer used the mild acid method with great results. You can read that in the response that I received from the customer:

“Thank you so much, Chris! I took your advice and removed some of the orange. Also, I added in some darker colors. I could not be more excited! I’m very happy. It is beautiful, or at least I think so. Thank you again for your help!!”

Another satisfied customer, or at least I like to think so.


Questions from Readers

This is my first time staining concrete. We got a stain in an ebony color. We did all the prep work, sprayed it on and it was moved around with an outdoor brush. Long story, short, there is absolutely no contrast and it turned out really dark, almost black even. How can we add contrast or light areas? Or maybe we could add green or blue into it? Any suggestions?

Answer from Concrete Decor

It sounds like you were using a reactive (acid) stain. Is that correct? If so, the ebony color is a black stain so it stands to reason that your concrete would turn black.

Here’s how you can bring about some change. First, if the stain is an acid stain the pH level needs to be neutralized. You can accomplish this by getting a small box of baking soda at the grocery store and dumping it into a 5-gallon pail of water. Then, mix it up and pour it out onto your concrete. After that, agitate the solution by moving it around on the surface with your broom. When you have fully treated the surface, you can then use your wet/dry vac to remove standing water. Do this again with clean water (no baking soda) and again agitate the surface and vacuum clean. Allow to dry.

Now you have a neutralized surface and can then apply acrylic stains in complementing colors of your choice. Once those surfaces are dry you can seal the concrete with a clear top coat.

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