The Enemy Is Efflorescence: How to Prevent Salt Deposits from Marring Your Masonry

The Enemy Is Efflorescence:
How to Prevent Salt Deposits from Marring Your Masonry.

Efflorescence. It’s a pretty name for the ugly crystalline salt deposits that mar porous building materials. The word, which comes from the French verb “to flower,” refers to the way salt appears to bloom from the surface of masonry, or brickwork.

As elegant as it is to say, efflorescence can be a real headache to prevent or treat without specialized expertise.

Salt is the culprit.

Efflorescence has found this column. Salt is the culprit.

Masonry – like practically everything that comes from the earth – includes soluble, or dissolvable, salts. When they come into contact with water, solvents or acid, they cake over your bricks and concrete, compromising your property’s appearance, often degrading the masonry, and sometimes signaling underlying problems that go to the heart of your building’s structural integrity.

The most common kind of efflorescence is caused by the interaction of salt and water in and on the surface of a porous material, like brick, stucco, mortar, cement, sand, clay, lime, backing materials and admixtures. Brick is notoriously vulnerable to efflorescence. But even wood can be affected by it.

Note, too, that there isn’t just one kind of salt. Common varieties include calcium sulfate, sodium sulfate, potassium sulfate, vanadyl sulfate, calcium carbonate, sodium carbonate, potassium carbonate, and manganese oxide. Depending on the type of salt in your masonry, the efflorescence can vary in color from white (most common) to yellow or brown.

You also need water.

The fabrication of masonry involves the use of water, which in cement and mortar mixtures will dissolve salts right from the very beginning. Water, of course, also comes from the elements – rain and snow. In addition, it can leak from sprinkler systems, cracks and gaps, and the ground. The salts dissolved by water move to the surface of brick walls and cement foundations. When the water evaporates, efflorescence is what’s left behind.

How to treat efflorescence.

A water rinse is one of our tools.

First, a word about prevention: It’s a lot easier to keep efflorescence from occurring in the first place vs. removing its salty “blooms” from your building, and you do that by isolating masonry from water and salt sources as early as possible in the construction process.

But once the problem occurs, you’ll have to shift your focus. If you have recurring efflorescence, that can be an indication of ongoing water intrusion. We can help address that before it moves deeper into the substrate and causes spalling, or flaking, as it deteriorates.

In addition to preventing recurrences of efflorescence, HSG also helps our clients remove the salt deposits. There are a number of ways to do this – all of which are most effective when the weather is relatively warm and dry:

• Brushing it off. A stiff brush can achieve wonders. You can try this yourself when the efflorescence is mild. Just be sure to wear a dust mask to prevent particles from reaching your lungs.
• Water rinse. We use a pressure washer, set at the widest-angle tip to avoid damaging the surface. Note, the act of rinsing can bring more salts to the surface, so this step may also require re-rinsing and brushing as necessary.
• Chemical cleaning. For tough salt deposits, chemicals are necessary. It’s important to have a professional perform this kind of cleaning because the wrong cleaners can stain or burn masonry, etch mortar joints, and cause additional deterioration through water penetration. There’s an art to choosing and mixing the chemicals you’re going to use. If it’s not done correctly, you can end up creating more problems than you solve.

How to keep efflorescence from returning.

Remember, efflorescence occurs when there are water-soluble salts in the wall, when there’s a path for the water to get into the wall and dissolve those salts, and when there’s a path for the water to reach the wall’s surface and deposit the dissolved salts.

The first thing to consider is how to keep water off the wall. Typically, we use a penetrating sealant that’s specifically designed to prevent efflorescence. The goal is not simply to seal the wall, but to remove water-soluble salts from within it. At HSG, we A) remove as much of those salts as possible from the wall; B) keep water out of the wall; and C) seal the wall to keep water from passing through the masonry and carrying dissolved salts to surface. Taking these three steps will effectively prevent efflorescence from marring your property’s surface ever again.