Simply put, black stains on
A dish soap, like Dawn, is a safe place to start. The surfactants in dish soaps are designed to remove oil and grease, they're gentle enough to be used without issue on your pavers. In a bowl or bucket, mix the soap with water and pour it onto the stain and agitate. Rinse and repeat if needed.
If you have greenish-black stuff on your concrete patio, it's probably mold, mildew, or moss. Damp or moist conditions from rain or humidity can encourage mold and mildew to grow in those nooks and cracks of concrete pavers or bricks.
Let us start by saying that bricks do not “turn black”. That is not supposed to happen. This black spot is developing probably due to one of these three things: excess moisture, dirt, or mold. Bricks are a completely natural material.
Use a Pressure Washer
If you have a small amount of mold or algae, you may find that the first two steps of drying out and sweeping the area is enough to remove it. If this is not the case, pressure washing is often quite effective in removing mold and algae from pavers, bricks or concrete.
You can use bleach and water. You'll want to use one part bleach, 10 parts water to create a good cleaning mixture. Or you can do like the professional painters do, and use TSP or trisodium phosphate for a great cleaning solution.
Instead of using the classic mold-killing treatment of chlorine, bleach, and water – which only kills the mold and doesn't also remove dead mold spores – you'll want to use undiluted vinegar.
Similar to cleaning pavers with muriatic acid, avoid an intense concentration of bleach, as it can damage the pavers.
To clean paver slabs, you can use a detergent, such as Dawn, or a vinegar-water solution that is gentle enough to effectively clean without causing damage to your concrete pavers.
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.
Sanding and chiselling will leave unsightly marks on your paving, bleaching can work well but you have to be careful not to kill your plants and dilute your bleach to the correct level, some people recommend using this method only in the winter months to avoid damage to plants but you still need to be really careful ...
Mildew is a surface fungi identified as a patch of gray or white fungus lying on the surface of a moist area. Mildew is easily treated with a store-bought cleaner and a scrubbing brush. Mold, on the other hand, can have colors that range from black to green and is often the result of a much larger infestation.
Mold generally looks slimy or fuzzy, tends to have a raised texture, and can come in a rainbow of colors, including deep green and black. Mildew is powdery, looks white or gray, always appears flat, and grows on surfaces.
Avoid Leaving Moisture
Mold requires water and moisture to fester and grow. So if you manage to rid the area of water, the mold won't be able to grow. Patio maintenance involves keeping the area dry and clean thoroughly.
White distilled vinegar is an affordable, natural solution to removing black mold. Its antibacterial acidic characteristics are exactly what you need to get the job done. Pour the undiluted vinegar into a spray bottle to apply to the area, or just go for it and pour that vinegar right onto the mold stains.
Mold needs to be entirely eradicated; otherwise, it will grow right back. This means that you have to clean far below the visible areas of growth with the right penetrating biocides. Simply wiping down your walls with some bleach or household cleaners might not be enough to get rid of a black mold problem permanently.
While it is possible to use bleach to kill mold as well, experts agree that vinegar is a much better option. Unlike bleach, vinegar can effectively kill the mold at the root, which means it's less likely to return. Vinegar is also less toxic than bleach, making it a better choice for household use.
There are a few ways you can remove algae from your green pavers, walls and fencing, some more effective than others. The simplest and most effective way is with HG algae and mould remover.
Decades of carbon emissions from factories and industrial plants fill the air in cities with invisible particles which settle onto our brickwork and cause carbon stains. If you look around any major town or city, you're likely to find black stains on the brick exterior of old buildings, monuments, and statues.
WD-40 may remove paint stuck to brick if applied directly and in large quantities, allowing it to sit on the surface for a few hours.
Black Carbon Stains
Over time, constant exposure to the elements will cause these black brick stains to build up. This can impact any type of brick, but most commonly in those in urban areas where there is more traffic.