How to Remove Stains on Decks and Patios
Whether your outdoor space is wood, stone or cement, it’s going to be prone to certain types of stains and discoloration. Here is your guide to keeping your deck or patio spotless and stain-free.
It’s true, stains on patios and decks can sometimes be a challenge to remove — whether they are greasy spots from the grill, soot, rust, tree sap or mildew. The good news is that with the right supplies and methods, you can clean up your space and keep it looking like new.
Stains on Wood Porches or Decks
When dealing with stains on wooden decks and porches, it’s important to get to them as soon as possible so that they don’t set into the wood permanently. Harsh chemicals should be avoided if at all possible. For example, using chlorine bleach can break down wood fibers and ultimately result in lasting damage. It can also harm the surrounding environment.
To get the most out of your wood deck or patio, be sure to seal or stain it every year or two and use these methods when combatting some of the most common stains:
• Barbecue Stains (Grease & Sauce): Basic dishwashing detergent that is designed to cut grease paired with a stiff-bristled scrub brush works wonders on grease spots and sauce splatters. Simply scrub the area with a mix of hot water and detergent and use a damp sponge or cloth to wipe up the loosened grease. Rinse the area with clean water from the hose.
• Candle Wax: Start by scraping away as much of the candle wax as possible using a putty knife or scraping tool that won’t put gouges into the wood. Then place paper over the area (a brown paper bag works well) and run an iron set on low over the paper to warm the wax. The wax will stick to the paper and you can just lift it away. Repeat this process until all the wax is gone, replacing the paper as necessary. Another possible solution is to use mineral spirits (usually found at your local hardware or DIY store). Wet a rag with the mineral spirits and place it on the dried wax until the wax is absorbed, rubbing gently when needed.
• Algae or Moss: Tough to remove, these stains need to be treated right away — before roots are formed in the wood. An oxygen bleach solution is the best tactic, and consists of a cup of oxygen bleach, ½ cup of borax and 2 tablespoons of dish detergent mixed with a gallon of water. Simply dip a scrub brush into the solution and scrub the stained area. Wait about 15 minutes before rinsing.
• Leaf Stains: Accumulated leaves on your porch or deck can start to decompose and create dark marks. When this happens, scrub the stain with a dish detergent and warm water solution. Then, soak the area with the solution for about 15 minutes before scrubbing again. Rinse with a hose. If the stains are stubborn, try scrubbing with an oxygen bleach solution, which consists of one cup of oxygen bleach and a gallon of water. Repeat as needed until the stains fade or disappear completely.
• Mold and Mildew: A common issue for decks in damp or shady spots, mold and mildew can be kept at bay with regular cleaning. Just wash down the deck or porch surface with a commercial cleaner/brightener. Apply with a roller, brush or garden sprayer and wait a few minutes before brushing with a stiff broom or brush. Rinse thoroughly with the hose. Be sure to read the label before using deck cleaners as some contain acids or chlorine that can harm vegetation.
• Rust: Metal outdoor furniture can leave rusty rings on your deck. To get rid of them, spray the stains with a 50-50 solution of distilled white vinegar and water, and let it sit for 10 minutes before wiping. An oxalic acid cleaner can be used on more stubborn stains. Simply follow the instructions on the package.
• Tannin Stains: Tree and plant tannins can cause dark stains on wood decks and porches when rain draws those tannins to the surface. To remove the black streaks, find a deck cleaner for tannin stains and follow the instructions.
• Tree Sap: When it hardens on the surface of your deck, tree sap can create persistent stains. Murphy Oil Soap applied directly on the stain can soften the sticky sap residue. Just let it sit for about 15 minutes before scrubbing with a brush and rinsing.
Stains on Cement or Stone Patios
Although cement, flagstones and bricks make solid patios that generally stand up to the test of time, they are also susceptible to certain stains. Use these tips to remove stains from cement or stone patios:
• Paint or Candle Wax: Scrape away as much paint or wax as possible with a putty knife or scraper. Then, using a metal-bristled brush and cold water, scrub the area until the residue is gone. If this technique doesn’t work, try using mineral spirits on the area. If you’re dealing with candle wax on cement and it’s still not completely gone, try covering the wax with plain paper and applying a warm iron so that the wax lifts off onto the paper. Repeat with fresh paper as needed until the wax is all gone. Paint stripper is effective for removing paint stains on concrete. Simply apply according to the instructions on the container.
• Dirt and Grime: The best remedy for cleaning up dirt and grime is water, a scrub brush and lots of elbow grease. Hose down the surface and scrub with a stiff broom. For especially difficult areas, try mixing dishwashing detergent with warm water and scrubbing. Afterwards, rinse the dirt away with a hose.
• Efflorescence: A white fog that sometimes manifests on paver or concrete patios, efflorescence is actually a natural occurrence that happens when salts in a stone rise to the surface. Efflorescence can be removed by scrubbing with a wire brush. If that fails, there are commercial removal mixtures that can be purchased at your local hardware or DIY store. Keep in mind, these removal mixtures often contain acid, so gloves and safety glasses when applying them are recommended.
• Grease Stains: Just like removing grease stains from wood, dishwashing detergent and warm water will also remove them from stone and concrete. Simply work the soap solution into the stain with a broom or brush and rinse with clean water. If the stain still remains, try adding ammonia to your soap solution and follow the same procedure. Scrubbing with mineral spirits is another option to try.
• Protein-Based Stains: This includes things like blood, juice, coffee or feces. These stains need to be addressed as soon as possible using a dish detergent and cold water solution. Flood the area with the mixture and work the stains with a stiff broom or scrub brush. Rinse with cold water.
• Soot: Bonfires can leave black soot marks on your patio. Luckily, they’re easy to remove with soap and water for the most part. If you have a more stubborn stain, apply a 50-50 mixture of muriatic acid and water. Gloves and eye protection are recommended for the latter.
• Tar and Heel Marks: Dish detergent and warm water is effective when removing tar and heel marks. If that fails, apply mineral spirits and scrub the area with a stiff brush. For really persistent stains, soak the area with mineral spirits and blot with an absorbent cloth until the stain is gone.