Zep Wood Deck & Fence Pressure Wash Concentrate cleans dirt and stains caused by algae, mold and mildew from outdoor wood surfaces, including decks, fences and shake shingles. The concentrated formula helps clean and brighten colors or prepare surfaces for painting or staining. The concentrate makes up to 20 gallons of cleaner and covers up to 5,000 square feet. Preparation: Do not allow product to dry on surface before rinsing, as staining may occur. Do not mix with bleach or any other chemicals as hazardous reaction may occur. For vertical surfaces, solution should be applied working from the bottom up and rinsed using fresh water from the top down to prevent streaking. Test pressure washer for surface compatibility, with and without the cleaner, in an inconspicuous area. Remove deck furniture and incompatible items from area. Rinse and allow to dry before proceeding. Saturate plants, shrubs and grass with water before and after cleaning. Moisten surface before cleaning. Application: See DILUTION CHART on bottle for proper dilution. Put pressure washer siphon tube into proper solution. Use low-pressure spray nozzle to apply solution to surface. Allow to remain on surface 5 to 1 minutes, but do not allow to dry before rinsing. Remove the siphon tube from the container. Rinse with the high-pressure nozzle. Allow to dry completely and apply a water sealer to protect the wood.