If you live in an area of frequent rain and sunny days, efflorescence and its passing may occur quickly. The process may take much longer in drier climates. Typically, efflorescence will stop developing in approx- imately 18 to 24 months.
Efflorescence can generally be expected to disappear over time, depending on the environment where the paving or brickwork is on a project. However, rainwater, being slightly acidic, can dissolve the surface deposit.
Efflorescence on pavers will eventually stop on its own after the salts in the pavers have dissipated. On the other hand, recurring efflorescence may indicate an ongoing problem of water intrusion that needs to be addressed before it causes permanent damage to the structure.
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.
Pavers must be clear of efflorescence before applying a sealant. If you choose to wait for efflorescence to fade away with time, it's best to wait 2-3 months (or even up to one year) before sealing to ensure the efflorescence is completely gone.
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.
Primary Efflorescence: This appears on newly built structures due to initial moisture. It often disappears after a few months without leaving permanent marks. Secondary Efflorescence: This occurs in older buildings, usually due to construction defects or unsuitable materials.
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 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.
Power Washing
We get this question a lot: “Can't we just power wash it?” Yes, you can certainly try. However, spraying efflorescent deposits with a power washer is the least effective way to remove the white stains from your brick and mortar.
Using a water-dampened sponge or garden hose, wet the area to be cleaned. Apply the cleaner and etcher solution to the area with a sponge or pump sprayer. Using a scrub brush, lightly scrub the area to remove the white powdery residue from the surface.
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.
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.
I attack the more tenacious efflorescence with a grinder wheel first, get the surface area as low as I can, then wet the area with water and squirt the acid directly over the efflorescence , rinse off and sometimes repeat the process .
Any efflorescence on the surface must be removed prior to painting as it is regarded as a poor and friable base that prevents paints and coating systems from adhering effectively.
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.
Although it can be unsightly and sometimes difficult to remove, it isn't dangerous or a sign of bad news to come. In most cases, efflorescence will resolve on its own.
Managing water movement in and out of your concrete and masonry is generally the easiest and most cost-effective means to control efflorescence. This can be accomplished by sealing your concrete, bricks, and masonry to prevent water from being absorbed.
Can a Dehumidifier Help? The truth is that a dehumidifier does nothing to counter or reverse the effects of efflorescence on your crawl space walls. This device will only help you dry out the crawl space air so moisture won't build up and cause condensation, mold growth, rust, and other problems.
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.
Once your concrete has dried, you can use either bleach or muriatic acid to remove efflorescence from your concrete sidewalk or driveway.
Similar to vinegar, lemon juice contains citric acid, which can effectively break down efflorescence. Squeeze fresh lemon juice onto the affected area and let it sit for a few minutes. Again, use a brush or cloth to scrub away the deposits gently.
No-one can say how long any incidence of efflorescence will last. It might be a few weeks; it might be a couple or three months; it &could be a year or two. There are so many factors affecting its generation and appearance, and its disappearance that an educated guess is the best we can manage.
Efflorescence alone does not pose a major problem, but it can be an indication of moisture intrusion, which may compromise the structural material. Building materials, such as concrete, wood, brick and stone, are porous materials. Porous materials can absorb or wick water by a process called capillary action.
Texture and Appearance: Efflorescence appears as a white or grayish powdery deposit on the surface of the affected material. It is often found in a crystalline or salt-like pattern. No Health Risks: Unlike mold, efflorescence does not pose direct health risks as it is not a living organism.