Efflorescence: What Is It and How Do I Remove It?
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It’s the chalky white residue that sometimes mysteriously appears on the surface of concrete (including your beautiful Rosetta Hardscapes pavers) in springtime.
Efflorescence (sometimes referred to as “efflo” in the industry) is a natural occurrence that can affect concrete, brick, stone, and other porous hardscape surfaces and shouldn’t be a cause for concern. Rosetta Hardscapes paver expert Hardscape Nate explains efflorescence, how to get rid of it, and what you can do to prevent it.
What is efflorescence?
Efflorescence is a white or grayish crystalline deposit of salts that can form on the surface of concrete.
What causes efflorescence?
The primary cause of efflorescence is water vapor migrating through the concrete via evaporation, bringing soluble salts to the surface. When the salts reach the surface, they react with carbon dioxide in the air and form insoluble calcium carbonate.
Will efflorescence damage my Rosetta Hardscapes products?
No. Efflorescence occurs naturally in virtually all concrete products exposed to moisture, but its presence won’t impact the strength and durability of your pavers and slabs in any way. Efflorescence is a cosmetic issue only.
Is efflorescence permanent?
No. The salts that comprise efflorescence are water-soluble, so the white haze that appears on outdoor patios may very well diminish a bit through the course of normal weathering. However, patio owners may choose to attempt its removal.
How do I remove efflorescence from my Rosetta Hardscapes pavers and slabs?
Scrub affected patio sections with a stiff-bristled broom or brush (not metal) and dish detergent diluted with water to safely remove most efflorescence. Rinse your patio with a hose afterwards.
For heavier efflorescence deposits that might resist brushing with soap, commercial cleaning solutions designed for concrete are available at many landscaping and home improvement stores. Because these cleaners often include acid and strong detergents, they should be used as a last resort and strictly following the product’s handling and application guidelines is strongly recommended. We recommend cleaning a small inconspicuous area first, to ensure the solution gives you the result you want.
Will efflorescence return?
Efflorescence will come back if the underlying problem isn’t fixed.
How can I prevent efflorescence from occurring or returning after I remove it?
Efflorescence cannot exist without water to dissolve and transport salts to the surface so eliminating or limiting extended water exposure is the prevention priority. Check around affected areas of your patio for low spots that may be holding water after rains or lawn irrigation sessions. Identify if you have downspouts spilling directly onto your patio. We recommend working directly with your professional installer to troubleshoot and address these instances. Remedying these types of situations should go a long way toward reducing occurrences of efflorescence.