Selected Answers

From Zenith Czora of Durotech Industries, Inc. on May 1, 2017:
Not all concrete surfaces can be acid-stained. Som ...read more Not all concrete surfaces can be acid-stained. Some surface contaminants will inhibit the penetration of acid stains, which will affect the staining process. Concrete surfaces that have been exposed to hostile climates and traffic will affect the staining process. Surface preparation and the condition of the concrete itself, like its porosity, will determine the outcome of the staining process. Denser concrete will reduce the penetration of acid stains and might require mechanical preparation. Poor surface preparation will highlight inconsistencies like patchworks or filled cracks. Do not acid- etch the concrete as acid will destroy the mineral within the concrete that reacts with the concrete acid stains to produce the mottled look. The concrete surfaces needs to be dry.  There should be no  moisture or water seep, which might affect the staining process. A small area should be tested to ensure that acid stain reacts with concrete to achieve the desired mottled look.

From Jeff Donius of Premier Veneers on April 27, 2017:
First, when you do a sample, choose an inconspicuo ...read more First, when you do a sample, choose an inconspicuous area, such as a closet, stairwell, utility room or area that will receive another type of floor covering. Second, to determine the presence of a coating that might inhibit the stain, use a small amount of water to check absorption of the concrete and then muriatic acid to check the reactivity. Third, do the sample, using at least 3 different colors. Fourth, rinse and seal the samples. Sometimes, the stain will take, in general, but problems will show up once the sealer is applied. Other times, the color will rinse right off - before sealing - due to an admixture in the concrete. Contrary to prevailing opinion, most concrete can be prepped to receive acid stain.

From Ron Adams of Hill Brothers Chemical Co. on April 24, 2017:
First, clean a small area to determine the best me ...read more First, clean a small area to determine the best method of prep. Then, do a small test with the acid stain to see if the concrete takes the stain. If successful, then proceed with the whole slab.