Over time your patio can collect dirt, hard watermarks and mould growth. These contaminates can wear down your patio and cause it to slowly decay. Clean these stains as soon as possible to prevent them from etching the patio surface or soaking deeper into the patio where they will be more difficult to remove.
Basic Cleaning Solution
Mold patios get dirt, food spills or other fairly easy-to-remove stains on them. You can remove these stains by using a simple mixture of soap and water. Use liquid dish soap that does not contain bleach as it could change the colour of your patio floor. Add several tablespoons of soap to a bucket of warm water, and mix it until the water is sudsy. Apply the soapy water to the patio with a scrubbing brush, and scrub it into the patio until you've removed the dirt. Rinse with clear water, and let the patio air dry.
Mold Cleaning Solution
Mold is a fungus that eats organic matter to survive. It also needs water and is therefore attracted to areas with excess moisture and humidity. If rain runs off your roof and onto your patio, mould likely will begin to grow. Mold ranges in colour from white to green to black and can appear furry or slimy. Prevent mould from growing by ensuring that your patio is properly drained and that the slats are far enough apart that water can flow between them. When you have mould, use a bleach-based mould cleaning solution, but be aware that it might lighten your patio's colour. You can make your own by mixing 1 gallon of water with 1 cup of bleach. Spray the solution on the patio, and let it sit for 1 hour. Scrub the solution into the patio and rinse it with clear water.
Mildew Cleaning Solution
Mildew is another type of fungus that will grow under the same conditions as mould. While it tends to be less serious of a problem than mould growth, mildew growth can make your patio look grey and can eventually etch the patio surface. To clean it, make a trisodium phosphate solution by adding trisodium phosphate to warm water according to the manufacturer's directions. Spray the solution onto the deck, and let it sit for several minutes. Scrub the mildew growth off and rinse with clear water.
Rust Cleaning Solution
Rust is another common stain on patios that is left behind by rusty water draining on your patio or by rusted metal cans or pots that have been sitting on your patio for too long. Clean the rust as soon as possible to prevent it from spreading or soaking into the patio where it may be more difficult to remove. Do this by sprinkling oxalic acid powder over the stains. Scrub the oxalic acid into the stain with a brush soaked in clear water, which will create an abrasive powder that will help grind away the stain.