Most issues with stained concrete that occur after application revolve around sealer failure or lack of sealer maintenance. Too much stain residue remaining on the surface when sealing is the most common cause of sealer failure on stained concrete floors. These residues are highly acidic, which can chemically alter the sealer film as well as act as a bond breaker by clogging the pores of the concrete. This is why neutralization and removal of stain residue from the concrete surface is such an important step in staining. If significant amounts of color can be seen on pieces of the failing sealer, chances are that excess residue is the cause of the failure. Stripping the sealer, neutralizing and cleaning the floor, (sometimes re-staining) and then re-sealing are the common fixes for this avoidable, but all too common problem.