Concrete stain applications are becoming increasingly popular with business and homeowners (and most likely you since you've found this page!). The cool looks that can be achieved with stains are making people forget about the traditional methods of floor coverings (like carpet, tile, wood, linoleum etc . . .) and look to the decorative concrete professionals to create something unique and durable.
Acid staining has some wonderful characteristics to it. The outcome is random, and the acid "takes" to the concrete differently in different areas giving it a "one of a kind" variegated appearance. No two jobs look the same! With many colors to choose from, you can transform even your old slab of concrete into something wonderful.
Even with all the great benefits of acid stains, there are some down sides. That random outcome (that gives your concrete a "one of a kind" appearance) is kind of a two-edged sword. One the one hand, after it is stained and neutralized, it could have a beautiful "never seen before" look to it and on the other hand, it could have an ugly "never seen before" look to it as well!
Most decorative concrete contractors that specialize in concrete staining with acid know how to get the color in the general direction that you're going for (with different staining techniques) but if you're attempting to do it yourself, you might run into some ugly problems.
Because of some of the problems associated with acid concrete stain, some contractors are utilizing water-based stains on a more frequent basis.
Water-based stains are definitely easier to work with. Environmentally friendly and with no need use any neutralizing methods on the the surface after the acid has been applied, these products are a nice option. The downside here is that you'll have to become a little more of an artist while applying water-based stains. What you see is what you get - if you spray a brown stain, it's going to look generally look brown and not a whole bunch more crazy changes are going to happen to it like it would with an acid stain.
Even with some of the limitations of the water-based stain, great looks are being achieved with different mottling and color variegation techniques. Going this route might just be the best option if you're not that adventurous!
Sometimes your concrete slab has got many problems going on with it - it may have many holes on the edges from carpet tack strips and there may be other patching issues that need to be done first.
If this is the case, a thin polymer cement overlay would be required to give you a new canvas to work with. Not only does this thin top coat help hide some imperfection in the surface, you can achieve a closer (not exact) color that you're wanting. When you produce sample boards with an overlay on it and then stained with a color (or several colors), you'll better know what the outcome will be with a particular stain (whether it be a water or acid-based concrete stain.
One word of caution though, most stain color charts in the industry show approximately what the stain should look like on a regular slab of concrete. When you apply any stain to a polymer cement overlay, you'll get a drastically different look (many time much brighter than expected). Samples are essential before you attempt any job.