Why Is Efflorescence Making My Pavers White?
Efflorescence on concrete pavers is a white, powdery substance that can indicate moisture issues that may lead to more serious problems when left unchecked. As paver design and installation specialists, we implement industry-leading practices to minimize the risk of efflorescence. Here are the causes of efflorescence on pavers and tips for preventing efflorescence.
Efflorescence on Pavers: Why Are My Pavers Turning White?
Pavers turn white primarily due to efflorescence, a natural process where water-soluble salts migrate to the surface and react with carbon dioxide, producing a whitish haze. Other causes include capillary blocking, abrasion, weathering, and dissolved salts. While this is mostly an aesthetic problem, this issue can be addressed through cleaning methods and preventive measures.
While efflorescence may fade over time, it would stick like a sore thumb on your glorious driveway, patio, or outdoor living space. It's important that you understand how this whitish cloud appears so that you can apply the proper solution.
Efflorescence on Paved Surfaces: Understanding Calcium Carbonate Reactions in Concrete Pavers
Efflorescence is primarily composed of calcium carbonate and other salt deposits that form on the surface of paving materials like brickwork or patio stones. It results from an interaction between cement used in manufacturing the paving and environmental factors such as ground conditions, weather, and atmospheric elements.
Calcium hydroxide can leach from the concrete slab. It forms a visible deposit on the surface of paving slabs.
Efflorescence can manifest on patio surfaces, including a concrete floor, brick patio, or other cement-based materials used on outdoor surfaces. Its appearance varies in texture, coverage, and visibility depending on the paving material and environmental conditions.
Generally looks whitish (sometimes with gray or blue tints) and temporarily disappears when wet
Ranges from powdery to scummy in texture, and from hazy to crisp in visibility
More evident in darker-colored paving materials
Can affect large areas, individual units, or partial sections of paved surfaces
What Causes Efflorescence on the Pavers?
Understanding the causes of efflorescence on the surface of the pavers enables effective prevention, treatment, and maintenance strategies. These aspects can preserve the aesthetic appeal and longevity of the paver surface.
1. Capillary Blocking or Calcium Hydroxide
Efflorescence mainly happens when soluble calcium hydroxide is transported through tiny pores within the surface. Insoluble calcium carbonate deposits will block the pores, forcing further reactions to occur below the surface.
This capillary action, driven by moisture from various sources such as rainfall or groundwater, carries salts to the surface of the pavers.
2. Abrasion and Weathering
Weather phenomena like wind, rain, and hail can wash away both soluble and insoluble efflorescence materials from patio surfaces. Acidic rain in urban areas can potentially accelerate the process.
In relation to this, regular foot traffic and vehicular use on paved surfaces contribute to the appearance of efflorescence on the surface of the pavers.
3. Dissolved Salts
Efflorescence is also caused by salts naturally present in paving materials or introduced from external sources like de-icing agents or fertilizers. These salts dissolve in water within the pavers and are carried to the surface.
As the water evaporates at the surface, it leaves behind crystallized salts, forming a white, powdery residue of efflorescence on the pavers.
4. Improper Use of Sealant
Non-breathable sealants can trap ground moisture, especially between the sand joints. This may develop hydrostatic pressure that can lift the coating from the pavers. The space between the pavers fills up with moisture and results in a whitish residue.
Incorrect sealant application can also encourage water to go under the paver, turning the pavers white. Using a cheap sealant with insufficient UV inhibitors can also create a whitish effect. When your old sealant wasn't appropriately removed, applying a new sealant might also result in efflorescence.
5. Poor Drainage
In some cases, poor drainage can magnify or exacerbate the efflorescence. For example, when you install new driveway pavers on top of an old base, there's nowhere for the water to go.
Unfortunately, the water would only hit the base instead. This would enable natural salts to stick to the moisture and leave a white deposit on the surface of the pavers.
How Long Will Efflorescence Last?
In most cases, efflorescence becomes noticeable three to six weeks after installation and lasts for three to six months. The duration of efflorescence is unpredictable and can vary greatly depending on numerous factors, including site conditions and climate. You may not even notice the gradual disappearance.
Efflorescence may continue as long as there is calcium oxide present in the paving units or bedding. This natural phenomenon can persist at a small scale, though the visibility of the deposits may decrease over time.
Damp, shady sites may experience longer-lasting efflorescence compared to open, sunny areas. Using an efflorescence cleaner on your patio can speed up removal.
How to Remove Efflorescence on Paved Surfaces?
As naturally as the efflorescence forms, it will fade over time. However, you can expedite this by learning how to remove efflorescence, whether it's through pressure washing, using an efflorescence cleaner, or hiring professional cleaners.
Try Pressure Washing
Water can pass through brick pavers and carry the dissolved salts to the surface of the bricks. The salt will stay even if water evaporates, leaving a whitish tint or crystalline mess. Pressure washing can help remove efflorescence.
Wet the area and pour some detergent onto the pavers.
Wet the area and pour some detergent onto the pavers.
Scrub the pavers from end to end. Focus on the areas where the white haze is more evident.
Avoid going beyond 1,500 psi to avoid damaging the pavers and sand joints.
Position the pressure washing tip at least 12 inches away from the paver surface. Rinse by section.
Pros
Effective for light efflorescence
Can be done by most homeowners
Cons
Risk of damaging pavers when not done correctly
Temporary solution if underlying issues aren't addressed
Use Chemical Cleaning Solutions
Another way to remove efflorescence is to use the best efflorescence remover for pavers, like OceanCare Calcium Releaser, Glaze 'N Seal Efflorescence Remover, and Eco-Etch Pro Concrete Etcher & Cleaner.
Dilute the efflorescence cleaner with warm water in a bucket. Follow the cleaner's instructions, although it's usually one part cleaner and four parts water.
Wet the surface, then blow off excess water. You'll only need a wet surface, not a puddled one.
Test the cleaner on a small area before applying it on a larger surface.
Use a watering can to apply the diluted cleaner on the wet surface. Let the mixture rest for at least 10 minutes.
Use a stiff brush to soften the white residue. Work in small sections at a time.
Rinse each area thoroughly using clean water. You may also use a pressurized garden hose. Check if there are no traces of foam left, making sure you properly cleaned the paver.
Pros
More effective for stubborn efflorescence
Targets the specific problem
Cons
Requires careful handling of chemicals
Could ruin surrounding vegetation or plants when not used properly
Call a Professional Cleaner
Recurring efflorescence might signify more serious problems. In such cases, a masonry contractor may need to perform costlier repairs to address the root cause and effectively remove efflorescence, prevent stains, and protect the paving stones.
Removing efflorescence from pavers doesn't guarantee it won't reappear. Persistent occurrences beyond a few months may indicate underlying issues requiring expert intervention.
Professional surface cleaning of small areas can be relatively inexpensive, ranging from $100 to $200. This is a good option if you want to prioritize safety, especially when handling toxic cleaning materials, like muriatic acid.
Pros
Access to specialized equipment and cleaning solutions for more effective removal
Time-saving and potentially less damaging to the pavers compared to DIY methods
Cons
Higher upfront cost compared to DIY solutions
Potential for over-reliance on professional services instead of learning preventive measures
Does Sealing Stop Efflorescence?
Sealing alone doesn't necessarily prevent efflorescence. You still need to address the main causes, particularly moisture penetration from beneath the pavers.
In most cases, sealing can be effective when moisture only comes from the surface. However, we generally recommend delaying sealing until efflorescence has naturally dissipated to avoid trapping deposits beneath the sealant.
For block paving and brick surfaces with sand joints, it's especially important to allow time for joint stabilization before applying any sealant. This guarantees that the pavement has properly settled.
How to Prevent Efflorescence in Pavers?
Prevention can eliminate efflorescence problems. Once you remove the white residues from your driveway or patio, you can take these preventative measures to stop efflorescence on the surface of the pavers.
Apply quality, breathable, and water-repellent sealant. Remember that non-breathable ones can trap salts.
Install a vapor barrier underneath the pavers to stop water from seeping up. You may also consider installing wall covers or roof overhangs to protect the surface materials.
Make landscape adjustments. Include an adequate runoff area to keep water moving away. Additionally, keep your water sprinkler systems away from the pavers.
When planning the design, our San Diego paver specialists use the proper bedding material and grading to allow proper drainage. We can use permeable paving geotextiles to stop salt absorption from the ground.
Related Questions
Is Efflorescence Harmful and Should I Worry About It?
Efflorescence is generally not harmful to concrete products and doesn't affect their structural integrity, although it can be unsightly and may indicate moisture issues. While it doesn't typically cause permanent stains, addressing efflorescence promptly can prevent more serious problems and maintain the aesthetic appeal of your pavers.
Why Is Efflorescence Cleaning Necessary?
Efflorescence cleaning is necessary to restore the visual appeal of your pavers and prevent the salts from continuing to crystalize on the surface of the pavers. Regular cleaning also helps identify and address any moisture problems that could lead to more serious issues when left unchecked.
How Do You Treat Efflorescence on Concrete Pavers?
Treating efflorescence on the surface of the pavers typically involves a combination of mechanical removal and chemical cleaning, often needing some elbow grease to achieve the best results. Scrubbing with a stiff brush and water may suffice for mild cases. Meanwhile, stubborn efflorescence requires a specialized efflorescence cleaner to penetrate the pores of the pavers.
How Do I Permanently Get Rid of Efflorescence?
You need to address the underlying moisture issues that form on the surface of concrete pavers to permanently get rid of efflorescence. While cleaning methods like using muriatic acid can remove existing efflorescence, preventing its recurrence involves improving drainage, applying sealants, and installing the paving properly.
How Does Vinegar Remove Efflorescence From Pavers?
Vinegar can remove efflorescence from pavers by dissolving the alkaline salt deposits due to its acidic nature. When removing efflorescence from pavers with vinegar, wash thoroughly with clean water to neutralize the acid and prevent any potential damage to the stones.
Conclusion
By understanding the causes and solutions for efflorescence, you can confidently maintain the appearance and integrity of your pavers. Paver designers at Aviara Pavers follow ICPI standards to install pavers properly to avoid efflorescence, so you can save on long-term maintenance while keeping the beauty of your outdoor spaces.