Concrete stain can peel or flake off for several reasons. Inadequate surface preparation, such as failing to remove existing sealers or coatings, can cause the stain to adhere poorly. Applying the stain over a contaminated or excessively porous surface can also lead to peeling. Additionally, using the wrong type of stain or sealer for the specific application or environmental conditions can contribute to the problem. Excessive moisture, improper curing or applying the stain too thickly can also cause it to peel or bubble. If you’re experiencing peeling concrete stain, it’s advisable to consult with professionals like Baird Foundation Repair to identify and address the underlying issue.