How to Clean Wooden Decks and Porches

• Weekly cleaning: Sweep deck and porch surfaces weekly using a long-handled push broom. Remove toys and other large items from deck or porch surfaces, as rainwater can’t evaporate from underneath them. Check the cracks between planks and remove any items stuck between the planks.
• Yearly cleaning: Once a year, scrub your deck and porch surfaces with a solution of laundry detergent and water or trisodium phosphate (TSP). Use a long-handled scrub brush, and scrub along the grain. Pressure washers (power washers) can damage wood, so use them with caution on wooden decking. Use oxygen bleach to remove mildew, as chlorine bleach can deteriorate the wood and interfere with its ability to hold sealant.
• Brightening decks: Pressure-treated lumber becomes dingy and gray after several years. Restore and brighten pressure-treated lumber with oxalic acid, available at hardware stores. This acid is naturally found in wood and won’t harm plants, but it can be dangerous if handled or inhaled. Always cover your skin and eyes with protective gear when working with oxalic acids.
• Regular maintenance: Seal wooden deck surfaces yearly or when water no longer beads on the surface. Start by removing old sealant with a stripper designed for this purpose. Use a long-handled paint roller to apply new sealant, applying the sealant evenly and with the grain. At minimum, strip and restain stained porches and decks every 3–5 years.
• Removing stains: Scrub deck stains with a solution of oxygen bleach and laundry detergent, or brighten the entire deck with oxalic acid. Sand away stubborn stains with fine-grit sandpaper and reseal.