Selected Answers

From Jeff Donius of Premier Veneers on September 21, 2017:
Some of the stains contain toxic chemicals in smal ...read more Some of the stains contain toxic chemicals in small amounts - not all - and safety precautions can easily be taken. Concrete sealers and curing agents can be mechanically removed or stripped, still allowing the floor to be effectively stained. I've never encountered a concrete floor where "free lime has leached out," thereby not allowing it to be stained. Yes, color range is limited, but if you want the floor to look like natural stone, you don't want bright or synthetic colors.

From Zenith Czora of Durotech Industries, Inc. on September 14, 2017:
i did a review of concrete staining few years ago. ...read more i did a review of concrete staining few years ago. Below are the advantages and disadvantages of acid stains. Disadvantages of acid stains include the following: colors are usually limited to earth tones. Stains contains toxic chemicals. Acid staining is not applicable to any surface that already has a concrete sealer or curing agent or to older concrete surfaces where free lime has already leached out. Surface preparations, application methods and the conditions of the concrete itself will determine the outcome.  Acid staining will highlight inconsistencies like patchwork or filled cracks. Advantages of acid stains: are as follows. Acid staining has outstanding durability,surpassing all other concrete coatings in terms of resistance and long lasting durability. It will not chip, fade, or peel off the surface to which it is applied. Its longevity is even increased when floors are sealed and/or waxed. It creates a variegated or mottled look like marble or other decorative color schemes and pattern.