Zep House & Siding Pressure Wash Concentrate removes dirt and stains from roof and siding caused by algae, mold, mildew and other sources. The concentrate is formulated for use in pressure washers and makes up to 20 gallons of cleaner. The product is suited for use on a range of materials, including hard coat stucco, brick, wood and vinyl or aluminum siding. 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.