You can't cover your patio with copper sheets, but you can spray on a liquid solution of copper that will soak into the top surface of the concrete pavers. This copper will stop the growth of the pesky green and black organisms in their tracks. The easiest way to apply the copper is to buy copper sulfate crystals.
Algae and lichens prefer to grow in damp, humid areas. They need plenty of water to grow and often paved patios do not have sufficient drainage to stay dry. Algae also grows faster in shaded areas as water does not evaporate as quickly.
If vinegar does not do the trick, you can also try mixing about a cup of bleach for each gallon of water and using this as your mold-killing spray solution.
A mix of soap, baking soda and hot water and lots of scrubbing might also work, but it is very time consuming and you may need to go over the area several times. The best alternative is to use a specialist solution such as our Green Growth Remover which has been developed for this purpose.
What causes my patio to discolour? If your patio has patchy discolouration which is green or black, this is probably algae, mould or mildew growing. These growths are natural and won't really harm your patio itself, although they can make it slippier and keep it from looking its best.
Sealing the surface means no water can ingress into the fabric of the paving material. This will prevent the access of water providing the conditions for mould, algae and fungi to thrive. An excellent method of sealing is to firstly apply a coat of a biocide such as Centrecoat GS36 followed by a surface sealer.
Only algaecides can "kill" algae in pool water. However, baking soda can help clear up algae. Use both so you can restore sparkly, clean water!
Vinegar is acceptable to use for killing algae and cleaning a pond when it is drained. The acidic is good at lifting away the stubborn algae deposits and stains without damaging the liner material.
Mild detergent and water.
Mix some mild dish soap with water in a bucket to create suds, then use a brush or a sponge to scrub the surface of the pavers. If your pavers are textured or have intricate designs, this cleaning method can be gentler than a power washer.
The acetic acid in vinegar is a little stronger than acid rain, so exposing your pavers to this substance can lead to bleaching, corrosion and the loss of protective sealant.
Baking soda has low-abrasive properties, making it an excellent cleaning material for stuck-on grime and tough stains. Additionally, baking soda is absorbent, allowing it to absorb oils from the surface of the pavers, especially freshly oil spill on concrete pavers.
Mix Solution of dish soap and water, and use a brush to scrub the pavers clean. Make sure to rinse the pavers thoroughly afterward. This process may need to be repeated for tough stains. A recommendation is to do this every few months.
Cleaning your pavers with bleach has a lot of benefits: Disinfecting the Surface: Bleach is an effective disinfectant and can kill any bacteria or mold on the surface. This will help to prevent any health hazards from occurring. Removing Tough Stains: Bleach is also effective in removing tough stains from the surface.
Try Concrete Stain
The simplest path to reviving tired pavers is to apply an acrylic-based semitransparent concrete stain, such as Behr Premium Semi-transparent Concrete Stain ($27/gal.; Home Depot) or Valspar Semi-transparent Concrete Stain ($28/gal.; Lowe's).
Whether your patio is sealed concrete or cement, or even sealed concrete pavers, a bleach and water solution makes it easy to clean away built up soil, stains from leaves and pollen, mold, mildew and algae.
But as it turns out, copper pennies do a pretty good job of keeping algae away for a few days! Pennies made before 1982 contain copper and according to Google, “copper kills algae by binding to it, which damages the algae cells, causing them to leak and die.” I tossed in 10 pennies and waited for the results.
TIP 5: USE BLEACH OR VINEGAR
Oxidized bleach immediately starts to kill algae cells once it comes into contact with it. Bleach, however, should not be your first option, especially if the area you plan to rid of algae is near plants or grass.
Chlorine is still one of the most effective killers of algae so doing a super-chlorination of 10-20 ppm of chlorine can go a long way towards wiping out the algae. Liquid chlorine is an ideal shock for algae because it is fast acting and does not add cyanuric acid (CYA) or calcium to the water.
Hardware stores and home centers sell products designed to kill moss and algae, but you can save money by using inexpensive chlorine bleach or a non-creamy hand dishwashing detergent, such as Dawn.
When added to water containing algae, H2O2 breaks down into water and oxygen, releasing free oxygen radicals in the process. These free oxygen radicals can then react with and destroy the cell walls and membranes of algae cells, causing them to die off.
One of the best paver sealers is the Siloxa-Tek 8500. It is a penetrating concrete sealer designed to treat a variety of applications with an emphasis on hydrophobicity and reduction of water uptake. It dries completely clear with a natural finish that will not change the look or appearance of the susbtrate.
One of the keys to fungus and algae prevention on concrete is to control the flow and presence of water. For exterior surfaces, this is commonly achieved with a suitable design that uses gravity to channel the water flow away from the structure.