Note: If you do not properly neutralize the stain, then the sealer will lose it's bond, which will then have to be stripped and re-applied. If you leave too much residue you could have streaking or discoloration.
Water-based stains don't require neutralization or rinsing, and application tools can usually be cleaned with mild soap and water. After applying an acid stain, be sure to scrub the concrete with an alkaline soap to neutralize the surface and remove any stain residue.
For newly installed concrete, a minimum of 14 days of cure time is required, preferably 21 before an acid stain is applied. Once cured, you can use an acid stain. After the stain is applied, allow it to dry for at least 24 hours.
Over time, it can destroy concrete as the acid weakens its structure. This will cause scaling, pitting, peeling, and cracking. If the acid wash gets into the soil, it will evaporate on the surface but remain beneath the surface (just like it does with concrete).
Another application may be necessary if being done by hand. If so, ensure the concrete is rinsed thoroughly between applications. STEP 4 - FINAL RINSE: After the concrete is properly etched, neutralize with either sodium bicarbonate (baking soda) or soda ash.
Use a mild detergent as needed. You can use a water hose or power washer. If it is waxed then follow the instructions for Interior. If it is not waxed, then since there is no wax to protect the outdoor concrete sealant, it will wear and need to re applied occasionally.
Acid stains are a reactive coloring process that penetrates into the porous concrete surface. This is probably the most permanent of all coloring options but is usually limited to eight colors.
How deep does the acid stain react through the concrete surface? Concrete thickness can vary from ¼” to over 3′. However, depending on the finish (how it was troweled) and porosity of the concrete surface, the penetration of the acid reaction may be only 1/16″ – 3/16″.
A. Once that stain chemically reacts for a minimum of four to six hours—typically, you'll leave an acid stain overnight—it brings salts to the surface.
Avoid walking on areas that have been worked already. The acid stops reacting with the concrete after approximately 30 seconds so there is no need to scrub the surfaces for too long.
While you do not strictly need to seal your acid stained concrete, we strongly suggest doing so. Applying sealer will help maintain the appearance of your stained concrete. You can apply sealer once the stain has been neutralized, rinsed well and the surface is completely dry.
Left unsealed, the colors will fade, water marks may be an issue, and stains can penetrate leaving ugly oil spots where the service guy left his old jalopy parked on the driveway. It's pure and simple, the job just won't last without a good sealer.
Re-stain Your Concrete
After grinding down your concrete, you can now clean it and restain the floor. Ensure the floor is clean and dry. Take your new (and quality) acid stain and apply it to the surfaces. This should penetrate the surfaces properly and come up with a desirable hue.
If you choose to brush the stain, such as for borders or multiple colors, be sure to use a soft bristle brush, in a circular motion, to avoid back and forth straight line brush marks. If you intend to brush the overall area during staining, then it will need a second sprayed only coat to help hide any brush marks.
If you wait longer than 72 hours, the overlay may become so hard that the stain cannot penetrate and react properly. Proper surface preparation includes but is not limited to dry sanding, mineral acid etch, and scrubbing, is always recommended when staining overlays.
Acid stains or Chemical stains react with the lime in concrete and color the concrete whereas concrete dyes offer transparent colors to the concrete surface.
When properly designed and installed, acid-stained concrete and decorative concrete overlays are almost completely unaffected by water. Moisture may and does pass through the concrete and sealer used in acid stained concrete flooring, but as it evaporates, it leaves no lingering effect.
Cons of Concrete Staining
It doesn't improve the floor's strength or durability, and doesn't change it resistance to spills or damage. If you'd like to protect your floors, we recommend combining it with another method (see point above) or opting for a decorative epoxy.
Neutralize: Mix 4 cups of baking soda to 1 gallon of water in your large 5 gallon bucket and pour it into the now empty watering container. Or use 4 ounces of household ammonia to 1 gallon of water.
Yes, the color of stained concrete floors can be changed. There are several methods available to alter the color of stained concrete, including acid staining, water-based staining, and concrete dyeing. These methods allow for the application of new colors to the existing stained concrete surface.
Etching is a deep cleaning process that maximizes the bond between paint or protective sealants and the surface of the concrete. Without proper surface prep, you could end up with a coating that flakes or rubs off much sooner than it should.
Etching is a crucial step in preparing concrete for painting. It gives the surface tooth to adhere to, so your paint is more likely to stick for a long time. Most concrete paints require etching and if they don't, do it anyway. Don't skip this step if you want a long-lasting painted concrete floor.
A white haze, white streaks or white, powdery dust on the surface after drying is caused by waiting too long before rinsing or by inadequate rinsing. The white powder is a combination of cement particles released from the surface and a precipitate byproduct of the etching reaction, insoluble calcium phosphate.