Why Did My Deck Stain Darken or Turn Black?
There has always been some concern for deck owners as to why a deck stain can darken or turn black in color after a couple of years. There typically are a few reasons why this may occur for any brand of deck stain.
Improper Curing of Deck Stain
When a deck stain does not cure or dry properly it can remain tacky for longer than it should. This can result in embedded dirt, grime, and/or tree pollen. These trapped contaminants can have an increased effect on mold and mildew growth darkening the deck stain. Improper curing usually happens from over applying the stain.
Mold/Mildew Prone Climates
In very hot and humid climate types, mold and mildew can actually begin to form on the surface of a deck stain causing it to appear darker. In extreme cases, mold and mildew can grow below or in the stain further darkening the appearance.