This effect is called efflorescence. It's also caused if the clay used for making bricks contain Pyrite and the water used for pugging the clay contain gypsum. Vinegar (acetic acid) solution with water can be used for cleaning of efflorescence in the masonry wall.
An acidic cleaner, such as PROSOCO's Sure Klean Light Duty Concrete Cleaner, and Sure Klean Vana Trol can dissolve efflorescence more effectively.
As stated previously, most efflorescing salts are water soluble and many will disappear with normal weathering unless there is some external source of salts. In general, most efflorescence can be removed by dry-brushing followed by flushing with clean water.
A: Yes. We recommend using a 50/50 solution (equal parts of CLR Calcium, Lime and Rust Remover and warm water.) Apply solution to the affected stained areas of the windows using a damp cloth or sponge.
The acidity in the vinegar helps remove the efflorescence and calcium deposits by breaking down mineral crystals. After cleaning the surface, let dry for 48-72 hours (moisture content below 25%).
Dilution ratio is 20–50% vinegar in water by volume. For most cases of efflorescence a 25% solution works well.
Regular white vinegar with 5% acidity works fine. With a sponge, apply vinegar to the area with efflorescence and clean it a circular motion. Leave the solution on the area for 10 minutes before rinsing the area thoroughly with water. Vinegar works best on surfaces like stucco, but can also work on concrete and bricks.
RadonSeal Efflorescence Cleaner can be safely used on poured concrete, concrete blocks, bricks, stucco, pavers, and artificial stones. The cleaner chemically breaks down and removes efflorescence, lime deposits, metal salt stains, and rust deposits.
Efflorescence of this type can be removed with a dilute acid solution (such as one part hydrochloric acid in 9 to 19 parts water or one part phosphoric acid in 9 parts water). After treatment the area should be washed with clean water to remove all acid.
To start the maintenance process, you can use a solution of regular dish soap and water along with a stiff plastic scrub brush. Avoid using a wire brush, as it can dislodge wires and create rust marks on the surface.
In all but very extreme cases, efflorescence will stop as capillaries in the stone become blocked by crystallized salts. Once the process stops, the white deposits will eventually wear off with use and exposure.
And that is to add 1/2 cup of baking soda to one gallon of water. Mix the baking soda into the water and apply it to your stones. This will totally neutralize the muriatic acid. Rinse the stone with water and you're done.
Efflorescence occurs when water soluble salts travel to the concrete surface. The mineral salts might be a result of the cement hydration reaction or can come from many other sources like sulphate rich sand. Porous concretes, masonry and mortars will be more susceptible to the migration of salts to the surface.
Efflorescence Remover Starts Working Straight Away
On surfaces suffering from heavy contamination, the product will quickly start to 'fizz' as it dissolves the salts. It can be re-applied at any time, but always remember to wash it away and rinse down surrounding areas.
Efflorescence is removed by natural weathering processes - as rainwater is slightly acidic, it gradually dissolves and washes away the deposits. The process may also be assisted by warm dry weather when the deposit is blown away.
Efflorescence doesn't cause long-term damage to your stones, but it can make them look dull and white. Treating your paving stones with diluted muriatic acid removes the deposits and helps them look good as new.
Hydrochloric acid is a purer and more toxic form of muriatic acid. Hydrochloric acid has a normal pH of 1.5 to 3.5, while muriatic acid has a pH of about 1 to 2. Muriatic acid is also less potent because it's diluted with water (usually around 31.5 percent HCl) and contains impurities like iron.
Gator Efflorescence Cleaner will remove any efflorescence stains trapped in the concrete pavers, wet cast products & natural stone pores. It will make the surface look more clean and vibrant without discoloring or damaging the surface. This efflorescence cleaning is a necessary step before a sealer is applied.
Pressure washing can work to remove white efflorescence once the surface has thoroughly dried. The surface must be thoroughly rinsed to ensure that no residue remains. We also use a safe detergent to ensure a thorough clean.
Rinsing is not necessary! If you're simply using a vinegar and water solution to wipe and disinfect, you won't need to rinse. However, if there's also plenty of dirt and grime you're wiping away, you may also want to rinse with some extra water.
To do this, it is recommended that you treat your concrete walls with a breathable, penetrating concrete sealer like the Siloxa-Tek 8500. The Siloxa-Tek 8500 is able to prevent efflorescence from coming to the surface by reducing moisture intrusion and water infiltration.
A few major differences between efflorescence and mold growth: Mold grows, efflorescence doesn't. Mold can grow on just about any surface, whereas efflorescence doesn't spread. Mold is a fungus, whereas efflorescence is moisture that evaporates into salt deposits.