What are these White Deposits?
Efflorescence is often described as a white or ivory chalk-like deposit. Efflorescence is formed by water migrating through the masonry wall and out the pores. As it passes through the wall, it collects loose salt and lime and brings them to the surface. As the water evaporates, the salt or lime particles bond to the wall causing white stains.
Several products can be used to remove efflorescence. NMD 80 at a (4:1) dilution. When using NMD 80 for post construction cleaning, removing mortar smears, NMD 80 will not cause cleanup efflorescence.
EF-Fortless (undiluted) is formulated for one purpose which is to remove efflorescence (calcium chloride). EF-Fortless is a soap solution that counteracts efflorescence.
Not every "white deposit" on a wall is efflorescence!
- Calcite (calcium carbonate) will appear as a thick whitish deposit that usually forms over time. Calcite most commonly forms when excess moisture passes through the mortar joints, evaporating leaving behind white deposits on clay brick. For removing calcite from clay brick, use Calcite Presoak (ON CLAY BRICK ONLY) followed by NMD 80. For removing calcite from concrete masonry units (CMU) use White Scum Presoak followed by NMD 80.
Lime Run (calcium hydroxide) occurs as a steady release of calcium soaked water that creates a streak. Generally, lime run is treated just like calcite. When it is caught early enough, the normal wash process of NMD 80 (4:1) will be effective enough to remove it. For removing lime run the same procedure is used as removing calcite. Use Calcite Presoak (ON CLAY BRICK ONLY) followed by NMD 80. For removing lime run from clay brick use Calcite Presoak followed by NMD 80. For removing lime run from concrete masonry units (CMU) use White Scum Presoak followed by NMD 80.
White Scum (calcium silicate) is a result of improper use of new masonry cleaner reacting with brick and forming insoluble salts. This is created by un-buffered acid combining with silicates and clay. For removing white scum use White Scum Presoak followed by NMD 80.
Integral Water Repellent can sometimes bleed out of the brick or block, leaving behind a "white haze" that has a very similar appearance to efflorescence or white scum; however the removal process is completely different. For removal use OneRestore® (undiluted).
- Admixtures in mortar can bleed out leaving a white stain that can appear above and below the mortar joints. It looks similar to calcite and lime run. For removal use OneRestore® followed by NMD 80.
- Sealers applied incorrectly or failing can look white too. Knowing the type of sealer is helpful to find the correct remover. Not knowing the type of sealer, a variety of products needs to be tested to find the correct remover.
- Barium (barium carbonate) attempts to eliminate efflorescence by reacting with the soluble salts that cause it and locking it within the brick and hindering migration to the surface. For removal use OneRestore® following the "Deep Stain Removal Process."
As you can see by the pictures below, not all white deposits are the same. While some of them appear to be very similar, a simple test with water will help you determine if you have efflorescence or another variety of white deposit. Simply spray water on an affected area. If the stain disappears when wet and re-appears when dry, it might be efflorescence. If the stain is still visible, it may not be efflorescence.
Product specification sheets must be read for the details on "how to use". Always test prior to beginning full scale cleaning operations. Testing should confirm cleaning effectiveness on each type of surface and stain designated to be removed. Also test to determine the desired surface contact time and any potential for adverse reactions with adjacent materials. Allow test panels to dry thoroughly before evaluating final appearance and results.
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