It occurs when water leaves behind salt deposits on or in the masonry surface. It has a white or grey tint and can also appear as a powdery substance on floors or walls. In French, the word efflorescence means “to flower out” and in this case, it is salt that is flowing out of surfaces.
Clear water repellents, silicone and acrylic coatings also may help you remove efflorescence as well. The coating will absorb water across a masonry surface and prevent efflorescence from recurring. Plus, the combination of warm water and white wine vinegar has been shown to eliminate efflorescence.
The primary source of moisture for the occurrence of efflorescence is rainwater that penetrates or comes in contact with masonry. Rainwater will penetrate all masonry walls to some degree, more so if they are improperly designed or detailed.
Recurring efflorescence indicates a chronic moisture or water flow problem such as from ground water in retaining walls, around un-caulked window openings, non-full mortar joints.
Efflorescence itself isn't dangerous or harmful. It can lead to potential moisture problems that can cause structural damage to building materials. So it is important to take action when you notice efflorescence in your basement, on your paving stones, or on other structures.
We were told a diluted CLR solution would work. We tried this and it was a lot of work to scrub the surface clean of the residue and you have to be sure to rinse immediately because technically CLR is not for painted surfaces.
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.
Hydrochloric acid eats efflorescence. Wet the surface down first so that the acid is not absorbed into either the tile if it is concrete or stone or grout as it will bleach the pigmented grout.
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%).
Efflorescence and alkali salts can be removed by dry brushing with a stiff bristled brush followed by wet sponging the surface with a mild 5% solution of white vinegar (acetic acid) in water. The whole area should then be wiped down with a damp cloth and allowed to dry thoroughly.
Mold is a fungus, while efflorescence is moisture that evaporates into salt deposits. Efflorescence will turn into a powder when touched; mold will not. Efflorescence is white, yellow, or brown, while mold can be any color.
The Extent of the Issue: A small amount of efflorescence might not be a deal-breaker, but extensive or recurring efflorescence could indicate significant moisture problems.
Once the water source is eliminated, most efflorescence (also called Calcium Carbonate or limestone) can be removed with abrasive techniques. Dry brushing, light water blasting or light sandblasting followed by flushing with clean water. In large areas, rotary scrubbers with scrubbing pads may also be used.
Efflorescence itself is not harmful to human health. It is a natural process that occurs when water evaporates from concrete, masonry, or other porous surfaces, leaving behind salt deposits on the surface.
Efflorescence must be removed before applying a penetrating sealer.
The application of DRYLOK® Wet Wall Bonding Primer will minimize the reoccurrence of efflorescence when the surface is properly treated. Patch all holes and cracks with DRYLOK® Fast Plug®.
Efflock. Efflock is a high-performance, water-based, VOC-free, liquid additive designed for the bulk impregnation of cement-based building materials to protect against efflorescence and dampness. By controlling water absorption, efflorescence is locked and the potential for waterproofing failure is dramatically reduced ...
Once your concrete has dried, you can use either bleach or muriatic acid to remove efflorescence from your concrete sidewalk or driveway.
Water and moisture management should be the major focus of your prevention efforts. Efflorescence is far less likely to appear on dry surfaces. Remember, without water to dissolve and transport salts, efflorescence cannot exist. If possible, eliminating water exposure should be your objective.
High psi cleaning can remove efflorescence; however, you need to be careful not to use psi levels that are too high as that can make the situation worse and actually make the surface more permeable. Stick to no more than 2,500 psi for this job.
Vinegar is extremely effective against removing efflorescence from any surface, whether it be interlocking pavers, concrete pavers or bricks. You also do not have to worry about rinsing dangerous acids into the soil around your pavers.
If CLR Grease & Oil Remover is left on a surface for too long it begins to dry and can be very difficult to remove.
Efflorescence – Indicator of Water Problems in Structures
Yet, beyond its surface appearance, efflorescence strongly signals the presence of a water leak.