How to acid stain concrete

How to acid stain concrete


Stained concrete floors are an exceptional alternative to tiling and wood flooring. Projects are cost-effective whether you’re doing it yourself, or paying a professional.

Choices and options are endless when staining concrete as texture, gloss, color, and detail appearances vary depending on whether you use spray stain, roll on the stain, high gloss, low gloss, or styled concrete. Even if you have your heart set on travertine tile or slate flooring, don’t cross-stained concrete off of your list as acid stain concrete colors can be quite stylish and close to earth colors.

It’s easy to style concrete to look like tile flooring by using a cookie-cutter effect while the concrete is still wet. After staining and gloss are complete, the tile-like grooves will have a beautiful stone effect that flows throughout your home at less than half the price of porcelain tile.

Acid staining concrete

Acid staining of concrete produces a beautiful finish that can add character and value to any home or patio. While it is most often done by professionals, with the help of a knowledgeable stainer it can also be done on your own.

Here is a very basic rundown of the steps involved in transforming your concrete slab into a thing of beauty and joy forever. Remember that you should not acid wash concrete before you stain it, it will ruin the job.

First prepare the concrete

The first step to acid-stain your concrete is to ensure that it is free from any and all imperfections. The surface to be stained should be clean. No dirt or crumbs anywhere on the surface. It should also be free of stains.

Remember that each imperfection, stain or otherwise, will show itself after you have stained the floor and at that point will be almost irreparable. Therefore, you must ensure that your floor is absolutely clean and without a spot.

While it’s often recommended to use concrete soap, water, and a push broom, you can also take it a step further. By using an orbital floor scrubber, also called a swing machine, you will get the floor much cleaner and in turn, end up with a much nicer outcome.

If you pick the machine, using water and a black pad on your floor scrubber go over the entire floor in a back and forth motion to ensure you are covering the whole floor. Before the material dries that you have worked up, use a squeegee to move all the water and suspended dirt in the water out of the room you are getting ready to stain.

You should also look over the floor for any obvious defects that could affect it as a safe flooring such as large holes or elevated cracks. If holes exist in the flooring you want to stain, they can easily be filled with a polymer-modified concrete patching compound. Cracks on the other hand will need to be ground with a diamond grinder in order to get them level with the rest of the floor.

Test the stain before doing the whole floor

Next, pick an inconspicuous portion of the floor to be test-stained. It is vital that you know that the color and procedure used to stain the entire floor will work before you begin the process, so it is highly advisable to do a mock-up first.

Protect the surroundings and yourself

Now make sure that all your walls surrounding the floor are protected with plastic or a tarp. Tape with painters’ tape to the walls so as to ensure that only your concrete slab will be receiving treatment.

Also, at this time load your concrete acid stain solution into your sprayer. Follow the tool’s instructions. Lastly, make sure that you are properly protected–this protection includes a respirator, chemical gloves, and eye protection. Now you are ready to stain.

Note: Be sure your sprayer don’t have any metal parts that can affect the color of stain.

How to acid stain concrete floors indoors isn’t much different from outdoors

Apply the acid stain

Start spraying in the corner of the room that is farthest from the door. Steadily spray back and forth, backing up toward the door as you progress through the room. Spray in “typewriter” fashion, once you get from left to right end, move back to left and start going to the right again. You should always spray on a wet border, this way the stain will apply evenly.

You can also try to apply stain with a circular motion saturating the concrete, but not creating large puddles all over, although some pudding is fine. This will create more randomness and fade some of the overlaps.

Make sure that you have covered every inch of the concrete flooring. It is also important to remember that when using multiple colors for your staining, you should always start with the light colors. When the first color has dried, continue the process by spraying the next color in a direction that is diagonal to the first.

How long to leave acid stain on concrete to affect it

Now you must wait until the acid stain has dried completely. It usually takes a day before you should do anything about it. Once you see that it’s dry you can decide if you think it needs another coat or start cleaning the residue off the floor.

If you decide to do another round, repeat previous acid staining steps. If not, continue forward with cleaning.

Cleaning and neutralizing the acid

After you have finished the final layer of coloring, wait twenty-four hours before moving on to the next step. First, test your new floor finish by mopping a small area with a mop and soapy water. If the floor color stays, it is ready to be neutralized.

Neutralizing the floor stops the color reaction by using a chemical that will neutralize the chemical process going on in the concrete. There are several products available for this. Once you have prepared the solution, use a long-handled deck broom to agitate the floor and scrub the concrete thoroughly. Use a shop-vac or a squeegee to remove all the neutralizing agents and rinse with a clean mop and plain water.

To clean the residue off the floor using the floor scrubber (that you used to clean the floor if you got it), use a white pad, not the black pad. Black pads are very aggressive and may remove too much of the color on the floor. Apply water to the floor and use the neutralizer and continue throughout the whole floor.

Apply the sealer

Wait until the floor is completely dry before you do any sealing. Because different stain manufactures recommend different sealers for each of their products, be sure to check with them on what sealer to use.

Here is a guide on acid staining and sealing outdoors, the same kind of sealing can be done everywhere really.


This article explaining how to acid-stain concrete is only a brief overview of the entire process. Of course, after you have stained your concrete, you will need to seal it. This will help the color to stay fresh and vibrant for years to come.

It is important to note the difference between painting concrete, and staining concrete when choosing what type of flooring to install. Painted concrete has a layer of paint set on top of the concrete itself and dries as one solid color.

Stained concrete changes the concrete structure at a molecular level using an acid-base to mix with the compounded minerals. This is why, depending on the color of the stain being used, stained concrete flooring has a varying rustic pattern as real stone or slate would.

Besides color patterns, you can also choose your texture gradient based on the thickness of the stain you’ve opted for, whether it be roll-on or spray-on. Several layers and tones will change the way the concrete feels or lays.

Match it to your kitchen theme, or stone fireplace setting and furniture. Either way, your guests will be amazed to find that your unique flooring style is not imported from Spain or Italy, but is actually your own variation of stained concrete flooring.

The quality of stained concrete flooring is competitive. Wood flooring can easily warp or lose its luster, but a concrete stain is durable and holds its shape and shine for years. Tile flooring can crack, but once the concrete is sealed, not even water or heavy furniture can damage it.

Stained concrete is easy to clean and doesn’t stain or scratch like carpet or some woods will, yet it is just as beautiful as some of the most expensive stone floors.

When choosing flooring for your home, office, or even outside porches and barns, be sure to take stained concrete flooring into consideration.

Whether you’re on a tight budget or have a few extra dollars to spend, want a stone texture or porcelain shine, stained concrete is an appealing variation over your standard flooring choices that can be molded to fit your exact expectations.