This is a brown acid stained concrete floor project that we did in a tack room being built in Copper Canyon, TX. We normally spray our acid stains, which is what produces that popular marbleizing effect. Brown acid stain often creates brown and black shades depending on how it's applied and at what concentration. Applying more coats or increasing the acid stain concentration can create a darker floor with more blacks running through it. The magic of acid staining is how easily it creates multiple tones on concrete. However, there are some floors that are not ideal for acid staining.
So how can we tell if your concrete floor can be acid stained? First, we always keep in mind that acid staining is an imperfect process; there will always be some areas that are less than ideal and that's what gives it personality. But less than ideal does not mean ugly is ok, just that some areas look different from the rest of the floor.
The first thing I ask a client when I get a call about acid staining is, "What's on the floor now?" The answer will tell me whether we can do a direct acid stain (stain your existing floor) or if we need to apply a microfinish overlay (a thin, smooth coat of concrete that resurfaces the floor) first, then acid stain that. Some other questions I ask are:
Is it new construction or a remodel?
Is there tile, linoleum, wood, laminate, or carpet on the floor?
If there was carpet, was the underpad glued to the concrete floor?
Is there oil, battery acid spills, paint, or anything else on the concrete?
(Normally this is for exterior projects such as concrete patios, sidewalks, or driveways)
The ideal situation for direct acid staining is new construction projects (interior floors that have not had carpet, linoleum, wood, or tile on it) and exterior projects like patios, driveways, and sidewalks that have not been painted.
Less than ideal, but not impossible to do, are interior floor remodels simply because any imperfections left behind from the previous flooring (tile, linoleum, wood, laminate or carpet) will show up to some degree in the final acid stained floor. That doesn't mean we can't do a direct acid stain on remodels, just that it's a little trickier, as you can see in the next project.