On your basement wall, this often appears as a white powdery substance that can occasionally sparkle under lighting. In terms of composition, efflorescence consists of a collection of water-soluble salts; it can appear in a variety of different colors depending on the type of surface it appears on.
It has a white or greyish tint and consists of salt deposits that remain on the surface after water evaporates. In addition, efflorescence can appear as a powdery substance on floors and walls and requires special care to treat.
The easiest way to determine if it's efflorescence is to spray water on the substance. If it's mold (or a spider web), it won't change much. If it's efflorescence, it will dissolve.
Often confused with mold growth, efflorescence is a white, chalky, crystal-looking substance (whereas mold is more commonly green, black, or blue… although there are white molds).
WHEN WILL EFFLORESCENCE FORM? Efflorescence may appear immediately or within a few months of product casting, but since precast concrete decreases in porosity as it cures, efflorescence is much more of a short-term condition here than in concrete masonry construction.
The good news is that efflorescence is completely harmless, not detrimental to the blocks, can be removed and will gradually disappear over time.
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.
The truth is that a dehumidifier does nothing to counter or reverse the effects of efflorescence on your crawl space walls.
Indications of Moisture
Efflorescence alone does not pose a major problem, but it can be an indication of moisture intrusion, which may compromise the structural material.
Efflorescence is the white powdery substance formed on the wall surface due to water seeping into the exterior wall. When water enters a wall and later evaporates, it leaves various soluble salts on the surface, disfiguring the wall.
It is common for people to confuse mold with efflorescence. Efflorescence itself isn't dangerous or harmful. It can lead to potential moisture problems that can cause structural damage to building materials.
Since efflorescence is basically a crystalline salt left behind as moisture evaporates through and off of a surface, you can expect it to be shiny, reflective, and fragile, crushing to a fine powder or dust under a fingertip.
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 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.
A solution of baking soda (sodium bicarbonate) and water (Approx. 1 lb. Of baking soda per 5-gallons of water) can be used to neutralize the stain. The solution should be applied until it stops fizzing.
Efflorescence Effects
Besides, deposits might grow and cause adhesion problems, if not properly removed before repainting. Other effects are physical damage to the structure and property value's reduced value.
Unlike mold, efflorescence isn't normally harmful to human health, but it can cause mild irritation if inhaled or if it comes in contact with the eyes. Even so, efflorescence doesn't usually float freely in the air as dust. Pressurized water can dissolve efflorescence and clean away the mineral deposits.
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.
Preventing Efflorescence
It takes much effort and time to clean off the residual salts of efflorescence therefore, the best course of action is to prevent it from ever happening again, or the first time. Simply sealing concrete from water penetration (using a penetrating sealer) will help prevent efflorescence.
Fortunately, there are several waterproofing solutions that can help to eliminate efflorescence and prevent it not only from ruining your property's overall appearance, but also from causing serious structural damage.
But if you wall has a high salt content, the efflorescence could develop again and again. The first thing to do is to take steps to keep water off of the wall as much as possible and see what happens. Consider a penetrating sealant that is specifically made to prevent efflorescence.
A wipeable vinyl paint may be the answer as this tends to stick better than a matt emulsion paint and it is hard wearing. Efflorescence is a white fluffy substance caused by salt coming out of the plaster which normally occurs from water penetration or moisture built up in-between the inner wall and the exterior wall.
Efflorescence should not stop you from finishing a basement. A contractor should remove severe deposits and properly seal any concrete before moving forward with a basement remodeling. The problem should never be ignored, since moisture can easily ruin a newly finished basement.
Using low alkali Portland cement can help reduce efflorescence. A well-graded aggregate, using a low water-to-concrete ratio, and preventing premature evaporation of water during curing are all good ways to reduce mineral salts. And finally, water sources used in construction should be clean, potable, and salt-free.