Above and below are several acid-stained concrete floors in a luxury condominium loft building in Royal Oak, Michigan.  We didn't do the original staining in these units, but we are asked to refurbish the floors every time a tenant moves out.  These 5 floors have been cleaned, touched up as necessary, and then re-sealed.

     Below are examples of some of the damage that is done to the floor by tenants.  In the first two photos below, carpet or matting with a rubber backing was placed over the sealed acid-stained concrete.  When the coverings were removed, they pulled the sealer and stain right off of the concrete.
     The next two photos also show damage caused by carpet or matting with a rubber backing.  In these two instances, however, rather than removing the sealer and stain from the concrete, the black rubber came loose from the backing and stuck to the concrete.
     Repairing acid-stained concrete can be done but is not easy.  It takes a thorough knowledge of sealers, and chemical stripping agents, as well as training and skill in faux finishing.  Our best advice is that if you have a new acid-stained concrete floors, do not place anything on it made of plastic or rubber, or containing adhesive.