What is Efflorescence?

Efflorescence occurs when a white, powdery substance seems to grow on the surface of your grout. It can look like patchy discoloration or a bloom of some kind of fungus. If it’s severe, efflorescence can appear thick and bubbly. It could even clog your drain.

But it’s not organic growth; efflorescence comes from the mineral deposits within the grout. Certain conditions cause these compounds to rise to the surface, where they create a white, yellow or tan haze over your tile and grout.

What Causes Efflorescence?

Efflorescence is a phenomenon that happens when too much moisture gets into the grout. Because the grout contains salts and other water-soluble compounds, it’s susceptible to efflorescence. The moisture dissolves the minerals. Then, as the moisture evaporates from the porous grout, the minerals rise to the surface. However, they can’t evaporate along with the water, and their residue remains on the grout.

Porous tiles are also prone to efflorescence. Therefore, you often see it on terracotta tiles and travertine flooring as well as the grout between the tiles.

Efflorescence vs. Mildew

Grout is notoriously tricky to keep pristine. Besides developing efflorescence, grout also seems to create the perfect environment for mildew growth. Identifying the problem correctly will help you take the right action to prevent and correct the issue.

Mold and mildew are organic materials that grow on surfaces that are frequently and continually exposed to moisture. Mildew often grows on the grout and flooring in showers and bathrooms because of the high humidity in that environment. 

While mold and mildew can be just as unsightly as efflorescence, they have the following differences:

  • Mold and mildew usually look darker, whereas efflorescence appears light in color.
  • When you rub it, efflorescence will transfer to your finger as a white, powdery substance. Mildew stays in place when touched.
  • Mildew and mold grow. Therefore, they spread over time. Efflorescence doesn’t change much after it appears.
  • Efflorescence dissolves in water. Mold and mildew don’t.

Is It Latex Migration?

Latex leaching, or migration, is another problem that can affect tile floors. It is also caused by excess moisture and creates a similar light-colored residue as efflorescence. However, latex leaching creates a harder residue. It’s not powdery and soft, like efflorescence.

Can You Remove Efflorescence From Grout?

The same solutions to remove efflorescence from grout won’t necessarily work on mildew, and vice versa. Efflorescence isn’t unsafe or dirty. Therefore, you don’t have to remove it. However, many people choose to remove efflorescence from grout because they don’t like the way that it looks.

On dark grout, the light patches that efflorescence creates make the dark areas look like mildew. Therefore, you should inspect the material thoroughly to determine what you’re working with before you try to tackle the problem.

Use a Stiff Brush

A stiff nylon brush can remove efflorescence without damaging the tile. Simply use the dry brush and moderate pressure to scrub the powdery flakes off of the grout. Don’t use a wire brush, steel wool or abrasive sponge, though. These products can scratch the tile and damage the grout.

Use a Mild Acid

Vinegar is an excellent product for keeping floors clean. It also helps to remove efflorescence from grout. Here’s how to use it to clean your grout:

  • An hour before you plan to clean the grout, saturate it with fresh water.
  • Create a solution of equal parts water and white distilled vinegar.
  • Dip a stiff nylon brush into the solution, then scrub the grout lines with it.
  • Rinse the grout with fresh water.
  • Dry the surface with a towel.

If the vinegar solution doesn’t work, try using undiluted vinegar. You can also purchase a commercial product that’s designed for removing efflorescence from grout. If you use this, follow the instructions on the label to use it properly. You might also want to test an inconspicuous area before you use the product everywhere. 

The process for cleaning with a commercial solution is generally the same as using vinegar. However, you may have to add more water to the grout to prevent the acid from deteriorating it. You should also wear safety goggles and gloves.

Can You Prevent Efflorescence?

Cleaning off the efflorescence is only a temporary solution. The powdery substance will return if you don’t get to the source of the problem. Plus, if excess moisture is leading to efflorescence, it’s only a matter of time until the grout develops mold and mildew growth.

Ideally, you would want to prevent efflorescence to keep your tile flooring looking pristine. Taking steps to combat efflorescence before it starts also reduces the amount of maintenance that the flooring requires over time.

Acclimate Your Tiles

Have your tiles been stored in a humid environment, such as a warehouse or garage? If the inside of your home is drier, it can cause the tiles to leach moisture. Avoid housing unused tiles in moist locations. Allow them to acclimate to the indoor atmosphere before you install them.

Use a Sealant

Creating a waterproof barrier between the tiles and the environment helps to prevent efflorescence. In extremely wet areas, such as spas and showers, you can install a waterproof membrane behind the tile to limit its water absorption.

You can also seal the grout from the front surface. Penetrating sealer fills the pores and prevents water from entering or escaping. 

Never use a sealer while the efflorescence is present. This will make the problem permanent, and you won’t be able to remove it. It’s best to apply the sealant after installation, once the grout is cured. If you want to seal older tile, use the steps for removing efflorescence from grout first.

Reduce Humidity

Basements and bathrooms are usually more humid than the rest of the home. Use the ventilation system in the bathroom during and after showers to prevent moisture from lingering. Run a dehumidifier in damp basements.

After showering or bathing, use a squeegee to remove excess moisture from tile walls and flooring. Follow up by drying the surface with a towel. This will help reduce the amount of moisture that the tile absorbs and holds onto.

Use High-Quality Products

The product that you use to set the tile can affect the grout’s absorption. If the adhesive or mortar is absorbent, it will contribute to efflorescence. You can also find grouts that are designed to minimize this issue. For example, epoxy grout won’t transfer minerals to the surface. However, you could still experience problems with the grout if you have moisture issues that need to be remedied.

Install the Right Underlayment

Efflorescence can build up rapidly and abundantly on concrete. If your house is built on a concrete slab or you’re using concrete tile, make sure that you follow proper installation instructions. This includes taking measures to prevent moisture from building up beneath the floor. Hiring a professional contractor for your flooring needs will help keep efflorescence at bay.

Fortunately, efflorescence is fairly easy to remove. Plus, the methods that you use to remove efflorescence from grout will also minimize the appearance of mold and mildew growth. However, it’s important to minimize excess moisture in any area of the house to keep your tile looking great for years.