Use on above-ground wood installations (especially non-pressure-treated lumber), to protect the structural integrity. Prevents mold, mildew and other fungi attack, and dimensional change caused by water absorption. Use as a final finish or under an oil-base primer followed by desired paint or stain. EPA-registered, fungicidal preservative protects against surface mold, mildew, rot and decay. Water repellent resists water damage: swelling, warping, end-checking. 100% clear - reveals natural wood color and allows it to gray naturally. Gallon. Rustoleum / Zinsser Corp