Hard Floor Maintenance / Web Exclusive Features

Efflorescence 101: Identifying, Cleaning and Preventing the Substance

This piece will take a closer look at efflorescence, including what causes it, how to prevent it and how to clean it.

efflorescenceTile often requires regular sweeping, vacuuming and damp mopping to maintain a like-new appearance. Yet occasionally, a whitish, crystalline deposit on grout lines and tile surfaces resists standard cleaning methods. This frustrating substance, which is called “efflorescence,” can quickly turn grout lines from accents to eyesores and affect the appearance of the entire tiled area. Fortunately, efflorescence can be removed – and then prevented entirely.

This piece will take a closer look at efflorescence, including what causes it, how to prevent it and how to clean it.


Understanding the root causes of efflorescence can help you initially prevent or effectively address its occurrence. Efflorescence is composed of water-soluble minerals. These minerals typically originate from the substrate below the tile or from the ground below the substrate. When moisture below the tiled area evaporates, it transports minerals to the grout and tile surface. In many cases, efflorescence is the only sign of moisture, and often, it only affects the appearance – not the functionality – of the tile. Although efflorescence is caused by moisture, regular mopping with water does not typically contribute to it.

In exterior installations, efflorescence is often the result of moisture below the tiled area’s surface. However, in some rare circumstances, prolonged exposure to rain can cause efflorescence – especially with porous grout.


Some installers use grouts with efflorescence-resistance and additional precautions taken before tiles are installed can further help prevent this problem. For example, waterproof membranes installed close to the installation surface can prevent moisture from traveling beneath the slab to the tile and grout. Additionally, grouts and mortars with low absorption rates can reduce the likelihood of efflorescence. Penetrating sealers applied to the tile and grout’s surface form water-resistant shields that help keep moisture out.


If you notice a residue on a tiled surface, you should confirm that efflorescence is the cause of discoloration rather than mold or another problem. Note that efflorescence is almost always white, yellow or brown. Efflorescence will turn into a powder when pinched between your fingers, while mold will not. Similarly, efflorescence will dissolve in water, while mold will not. If you positively identify efflorescence, take steps to remove it right away. The sooner you catch it, the easier it will be to remove.


If you notice the efflorescence immediately after it forms, removing it should be relatively easy. Efflorescence is most soluble right after appearing, so if you catch it early enough, water may be enough to remove it. Simply scrub it with a stiff brush and clean water. Although just wetting the tile surface and grout line may appear to remove the residue, you may need to scrub fairly hard to actually dislodge it. After scrubbing, rinse the space thoroughly with fresh water. If you fail to rinse, dissolved minerals will remain on the tile’s surface - and it won’t be long before they reappear as efflorescence.

If water alone does not do the trick, you may need to use something stronger. Mild acids – including sulfamic or phosphoric – can often be used effectively against efflorescence, but stronger acids may burn fixtures and tile. If in doubt, consult with the tile and grout manufacturer about the safest cleaning products before you begin cleaning. Be sure to wear gloves when using any acid-based product and apply it with a sponge or brush. Also, take precautions to protect nearby fixtures. If there is no acidic cleaner on hand, you can easily create your own. Simply mix one-part vinegar with one-part water. If your problem is truly efflorescence, it should react to the acid immediately. After the acid wash, rinse the area with a mix of water and baking soda to neutralize the acid. Then, rinse the tile and grout again with clean water. Use acid cleaners sparingly.

As long as moisture continues to enter the tile system, the efflorescence will eventually recur – unless you break the cycle of moisture transmission. Applying a penetrating sealer is a relatively simple solution. Once the efflorescence is removed and the installation is rinsed, apply a penetrating sealer per the manufacturer’s instructions. The use of a sealer should not change the installation’s appearance.

Addressing Other Sources of Discoloration

If the above techniques do not remove the residue on your grout or tile, you may not be dealing with efflorescence. White residue occasionally forms on polymer-modified grouts if they are mixed with too much water, cleaned too soon or cleaned with excessive water. A solvent or strong cleaner may be required in these cases. Be sure to consult with the tile or grout manufacturer or try the cleaner in a small sample area to make sure the solvent will not affect the floor’s appearance.

Detergent residue can also leave tile installations with a cloudy appearance. In this case, simply rinse the floor as often as necessary with clean water, using a brush on the grout lines. Removing the dirty water after scrubbing will prevent the dirt from settling back into the tile surface and grout lines.

Clean tile and grout combinations can elevate the appearance of a home or commercial space. With the right products and cleaning techniques, you’ll leave your clients with the fresh-looking tile floors they envisioned.   

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