The look of an acid stained concrete surface is attractive for many reasons. Its unique finish characteristics are such that the uneven, ugliness of plain concrete becomes the star of the show. Acid stain will not mask, nor cover imperfections in the concrete, but it will use transform them into something quite attractive. Though professional skills may result in a more professional look, the artistic nature of the process allows the handy DIY’er to achieve a most satisfying look just the same. Just follow some necessary principals and behold the results. Keep in mind this is merely an overview and not detailed instructions. For best results, always reach out to a qualified decorative contractor in your area for your job. Let the experts handle it so you can best enjoy the results.
Please refer to the data and instructions from the specific manufacturer/supplier of your material. As with any concrete project, many unpredictable results can result due to unknown or unforeseen circumstances.
Getting Started:
To test the absorbency of the particular slab, you need to throw some water down and watch the results. You want steady and even absorption into the surface. Make sure to test the entire slab because you have to be able to remedy inconsistencies. If the water does not absorb steadily and evenly, curing agents or sealers may be blocking the surface, thus they will effect the application of the acid stain and must be removed. For sealer removal, many methods may be employed such as solvents, sanding, and grinding. If you choose grinding, be sure to use a proper disk, such as a grinding cup, to avoid swirl marks which will easily transmit otherwise. In addition, be sure to do a thorough cleaning with a good degreasing cleaner, such as TSP, to remove any grease and oil, paint drops, taping compounds, caulk, or other surface contaminants. If patching is required, know that it will take stain differently than the rest of the floor and will be visible (but better than a hole.) As an option, you may consider sanding the entire floor. It will often accentuate the high spots by opening up the pores even more allowing more stain to penetrate.
Finally, you’ll want to do one last washing to remove the remaining dust and debris. Water, detergent, and then wet vacuum it dry. Any streaks, lines, footprints, etc. can effect the final finish.
Applying the stain:
Manufacturers vary on when to apply stain. Many default to the standard 28 day cure time before staining is to be started. A few say 14 days. Some installers have had success after 3 days.
Keep in mind that the younger the slab, the more intense the color. This means that the older slabs requires a higher strength solution. So, if you’re trying to match stain for new concrete with stain for existing concrete it is going to be extremely difficult to achieve, and we do not advise that you attempt to do so. This also means that product cost can go down significantly when staining new concrete because of the ability to dilute the solution more freely.