When switching to a new brand of stain you should first remove any remnants of old coating that may be present. The same goes for switching to Defy stains. Unlike paint, wood stains are not designed to adhere to one another. When a new stain like Defy is applied over the top of an old coating it can jeopardize its performance and lead to premature failure of the stain.
Defy stains work best when applied to newly cleaned wood that is free of any old coatings. This allows the stain to penetrate the wood for maximum UV and water protection. When Defy wood stain is applied to an unclean surface or on top of an existing coating it may cause it to peel and flake because it is not meant to adhere to other stains. Proper stain penetration is the key to a long lasting beautiful finish.
Prior to switching to Defy stains clean the wood properly using a wood cleaner. If an old coating is present, use a wood stain stripper instead of a wood cleaner. This will soften the old stain making it easier to wash away using a pressure washer. After cleaning or stripping the wood use Defy wood brightener to complete the wood prepping process.
If you are unsure if the wood surface has an old coating on it, you can use the water drop test. Sprinkle a few drops of water on a dry area of the wood surface. If the water is absorbed quickly into the wood it suggests that an old coating is not present. Be sure to test several areas for better consistency. If the water beads up and is not absorbed into the wood that is a good indication that an old coating of some sort is still present and must be stripped away prior to switching to Defy stains.