can this product be applied over cabots oil based semi transparent stain after being on the deck for a year and a half ?

Thank you for taking the time to contact Cabot. In order to be effective, a stain must be able to adhere. Surfaces must be sound and may be dry or damp. If damp, the wood should be free of puddles and not feel wet. Be sure surface is free of all dirt, mildew stains, loose wood fibers and other foreign matter. Old loose stain should be scraped off and the edges sanded smooth for proper adhesion. Prepare previously stained or weathered surfaces with Valspar® Wood Cleaner to remove dirt and mildew stains or Valspar® AllIn-One Wood Prep to revive extremely weathered surfaces. Scrubbing with a stiff bristle brush is required to completely remove all dirt and debris. If you have any questions, please contact us directly at 1-800-877-8246 or info@cbgbrandreview.com. Sincerely, R.C., Digital Care Team