Fresco Deck’s Essential Guide: What is Efflorescence?

A white, chalky film creeping up your beautiful pool deck is never what you want to see as a homeowner, but it happens more than you would imagine. This mold-looking growth is called efflorescence, and while it may seem alarming, the good news is that it is not a sign of a more significant structural issue. Follow along with this guide to learn more about efflorescence, how to prevent it, and what to do if it appears on your concrete pool deck or patio.

What is efflorescence?

Efflorescence is the process by which crystalline deposits of salts appear on the surface of porous materials like concrete. These deposits form when an excess amount of water comes into contact with a surface with water-soluble salts. Usually taking the form of a white, fluffy or powdery formation, efflorescence can form in a range of colors and patterns, depending on the deck material and whatever chemicals appear in the water.

What causes efflorescence?

Efflorescence forms at the meeting point of water and water-soluble salts in a porous surface. The water carries the salts through the surface, then evaporates, leaving the salts in deposits at or right under the surface. Concrete, brick, and other similar materials can be perfect vehicles for this movement, as they’re naturally porous. The salts in question are either present within the building material or the grout used in construction, or they’re carried in with hard water.

Because a good deal of water is often needed to cause these deposits to form, efflorescence usually appears following heavy rains. This makes Arizona’s monsoon season a particularly effective breeding ground for efflorescence development. A concrete pool deck may find itself a victim to efflorescence growth, as well, if water is allowed to puddle around pools and seep into the concrete.

While not necessarily a structural problem on its own, efflorescence is a key indicator of water trapped below your deck’s surface, perhaps due to improperly sealed concrete.

Is efflorescence dangerous?

Not at all! While potentially unsightly, efflorescence is not dangerous. The salts in efflorescence deposits do not pose a respirable threat as they don’t naturally dislodge and become airborne; if they were to become free-floating particles, they would be mild irritants at the worst. Regardless, it’s important to take health and safety protocols when attempting to remove efflorescence from your space.

Efflorescence may affect sealants and coatings if not removed before new applications are started.

Despite efflorescence’s relative harmlessness, it’s recommended that you try to remove it as you begin to notice its build-up to best preserve your concrete decks and patios.

How do I remove efflorescence?

Efflorescence can often be removed through basic abrasive techniques. Depending on the severity of the salt build-up, professional concrete restoration techniques may be necessary. However, it’s important to know that due to environmental, chemical, or physical factors, there are cases in which efflorescence can only be mitigated and not entirely resolved. Talk to a professional if you’re concerned about being unable to remove efflorescence.

The best ways to remove efflorescence are:

1. Dry-brushing:

Dry-brushing should remove the majority of efflorescence. A mild detergent, like Dawn dish soap, and water alongside the mechanical brushing often does the trick to remove these salt formations. Remember to dry the spot where water was applied to help reduce the chance of further locking any moisture in the concrete.

2. Water or sand-blasting:

Depending on the surface, power-washing might be the answer to your efflorescence problem. A light water-blast or a sand-blast, followed by a cleansing water rinse, can often resolve efflorescence problems quickly. Using the least amount of water possible and immediately drying the surface will be critical here to ensure that crystals are not locked below the surface, ready to form deposits again once the moisture evaporates.

3. Acidic cleaners:

A weak acid solution or household vinegar may be necessary if the efflorescence proves to be water insoluble. These cleaners should be used alongside all appropriate health and safety guidelines and recommended professional instructions. Chemical treatment may also result in discoloration or other adverse reactions, so spot treatments are encouraged before committing to acidic cleaners.

It is recommended to remove remaining sealers and other coatings before trying to rid your deck of efflorescence. This will make it easier for you to reach the problem, and prevent water from getting trapped under the remaining sealant.

Four ways to prevent efflorescence:

1. Redirect water runoff away from concrete surfaces:

A well-constructed deck accounts for water accumulation and allows water runoff to be redirected to other parts of your backyard. Talk to a professional about concrete deck installation, and see how you can make the most of natural rainfall to protect your deck and irrigate your space.

2. Adjust irrigation to avoid overwatering:

Overwatering your space can be just as detrimental as a heavy rainstorm to the longevity of your concrete spaces. Avoid the overuse of sprinklers to keep your concrete drier and your environmental footprint smaller.

3. Seal your concrete pool deck every few years:

Keeping your pool decks chemically treated and secure requires some upkeep. Try to get your concrete resealed every few years to ensure a worn seal doesn’t lead to trapped water.

4. Make sure water doesn’t pool near your patio or deck:

Puddles of water, combined with a faulty sealant or a naturally porous surface, can lead to moisture trickling under the deck surface. Try to clean up spills and pooling immediately to avoid efflorescence from developing.

Following these easy steps will help minimize the effects of efflorescence on your pool deck.

Working with a professional concrete sealing company provides an added boost to your deck’s longevity. A properly applied hydrophobic sealant can prevent water from moving through the concrete, and semi-regular professional maintenance takes the problem off your hands, for the most part.

Contact Fresco Deck today to see what you can do to restore your concrete deck and prevent efflorescence from developing!