ZEP House and 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 Gal. of cleaner. The product is suited for use on a range of materials, including hard coat stucco, brick, wood and vinyl or aluminum siding. ZEP's All-in-1 Pressure Washing Concentrate removes dirt, oil, grease and stains caused by algae, mold and mildew. The concentrated liquid makes up to 26 Gal. of cleaner and can be used manually or in a pressure washer. The formula is ideal for cleaning siding, driveways, brick, wood, stucco, tile, vehicles and other surfaces.