What for preparation do you have to do to a older deck before using this product, such as power washing the older deck or sanding

Thank you for contacting Cabot. SURFACE PREPARATION General: Be sure surface is free of all dirt, mildew stains, loose wood fibers and other foreign matter. Surfaces must be sound and free of standing water. Remove loose splinters and replace severely damaged or rotting wood. Prepare previously stained or weathered surfaces with Cabot® Problem-Solver® Wood Cleaner, Wood Brightener or Wood Strippers. On severely weathered surfaces, sanding may be required to completely remove all loose wood fibers. Fill larger cracks with an exterior wood filler. Allow new concrete or masonry surfaces to cure for 30 days before coating with DeckCorrect™. Mildew: Any mildew stains present on the surface prior to application should be removed with Cabot® Problem-Solver® Wood Cleaner. Mildew stains are not caused by the coating, nor do they represent coating failure. This product contains agents that inhibit the growth of mildew on the coating’s film. If you have any questions, please contact us directly at 1-877-825-7727 or info@cbgbrandreview.com. Sincerely, R.C., Digital Care Team