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As winter unfurls its snowy cloak, our concrete roads, driveways, and walkways become battlegrounds. Mother Nature delivers freezing temperatures, snow, and ice. We respond with abrasive gravel and salt. The result is melted water and slush that can seep into unsealed concrete, where, upon freezing, Mother Nature gains a victory. Ice swells by 9% when it freezes, and this expansion can pop off the concrete above it, creating a pop mark—another victory for Mother Nature.
Once winter begins, the battle is set, but we can adjust conditions to secure a victory by ensuring our concrete is properly sealed to keep meltwater out. We can also prevent sprinkler and gutter water from causing similar damage to our driveways and sidewalks if we prepare in advance.
These elements are not merely inconveniences; they pose a significant risk to the integrity of stone floors and driveways.
This blog explores the profound impacts of these annual winter assaults on stone and concrete surfaces. It sets the stage for understanding their damaging effects and the science behind their interaction with our cherished stonework and concrete. Or, you can save yourself the reading time and simply call MARBLELIFE-ENDURACRETE to arrange a FREE review of your property to assess steps that can ensure you see Spring as a VICTOR. See why facility managers and property managers trust MARBLELIFE-ENDURACRETE's guidance as they refine their property plans to reduce maintenance costs over time. What works for large properties is also available at the individual residential level. Like all things, an ounce of prevention can save a pound of cure—and self-recrimination later.
The Chemistry of Salt and Its Effects
De-icing salts, including sodium chloride (common table salt), magnesium chloride, and calcium chloride, are widely used to manage ice on surfaces during cold months. These salts lower the freezing point of water, a process scientifically known as freezing point depression. By doing so, they prevent water from freezing at the usual 32 degrees Fahrenheit, keeping it in a liquid state even in colder conditions.
Interaction with Moisture and Cold
When these salts are applied to icy surfaces, they attract moisture from the environment. This reaction not only melts existing ice but also prevents new ice from forming. As temperatures fluctuate, this can create a cycle where melted ice re-freezes, leading to repeated applications of salt.
Corrosive Effects on Stone and Concrete
While effective for ice control, these salts can be corrosive. They attack the chemical structure of metallic materials they contact, leading to the application of anti-corrosion coatings on vehicle undercarriages. Porous stone and concrete suffer a different attack. While salts depress freezing points, they do not eliminate them. Instead, they delay freezing until the temperature drops sufficiently. While this makes car travel safer in the short term, it does not permanently halt water’s freezing within surfaces. The problem lies in the fact that ice swells 9% when freezing, and if caught within the pores of concrete or stone, it can create enough internal pressure to fracture the material. Look around on your next hike through the mountains, and you'll see the devastating impact freeze-thaw cycles have on stone surfaces over time. The pockmarks on concrete are a direct result of this phenomenon. In some areas, this is so severe that they install pockmarked concrete to camouflage the damage, a warped logic that creates more water collection points to freeze and crack the surface, merely masking the damage for a short time. Prolonged exposure to de-icing salts can lead to aesthetic and structural damage, impacting the longevity and safety of stone and concrete installations. The good news is that this can be prevented.
The Physical Impact of Slush on Stone Surfaces
Slush forms a challenging mix of snow and water from partial thawing and subsequent refreezing. This semi-frozen concoction often gathers on stone floors, concrete driveways, walkways, and sidewalks, where it is further compressed by vehicles and foot traffic. The pressure from this compaction forces the slush into surface pores and low spots. This compacted slush can then turn to ice, creating a slip hazard while also expanding within the surface pores, breaking up the unsealed concrete.
Factors Contributing to Slush Formation
Temperature Fluctuations: Frequent shifts between above-freezing and sub-freezing temperatures facilitate the rapid formation and transformation of slush and, at the other end of the cycle, ice. This freeze-thaw cycle repeats each time the surface crosses the freezing temperature point, even if it has been lowered below freezing.
Snowfall and Melting Cycles: Initial snowfall followed by warming periods leads to melting, which reverts to slush and then ice as temperatures drop again.
Environmental Exposure: Areas exposed to direct sunlight during the day and extreme cold at night are particularly prone to slush accumulation and ice formation as often as each evening. Depending on where you live, this cycle could repeat 30 to 90 times a season. In the south, this may be less frequent, but in the north, the beginning and end of the season can see this occur dozens of times.
Exacerbating Wear and Tear
The cyclical nature of slush and ice formation—freezing, thawing, and re-freezing—poses a severe threat to unsealed stone and concrete surfaces. This cycle initiates a series of physical changes and reactions in the material:
Penetration of Water: As slush melts, water infiltrates the tiny crevices and pores in stone or concrete.
Expansion During Freezing: The water trapped within these micro-cracks expands as it freezes, exerting outward pressure that can fracture the stone. Ice expands 9% when freezing. If your concrete has rebar reinforcement, these pressures are even higher, as rusted iron will expand in volume by 600%, explaining why we frequently see exposed rusted rebar on sidewalks and bridges. It’s not the scar of a vehicular impact, but rather evidence that a seal failed, or an area of concrete was missed, allowing water to reach the rebar. Worse still is water laden with salts, as these accelerate the corrosion process.
Cracking and Spalling: The force of expanding ice can cause visible cracks and spalling, where fragments of the stone surface break away, unable to withstand the internal pressure created by the ice’s expansion.
Progressive Deterioration: Each freeze-thaw cycle cumulatively exacerbates the damage, gradually reducing the structural integrity and aesthetic appearance of the stone.
Mitigating Strategies
Proper Sealing: Applying a high-quality sealant creates a barrier against water penetration. This should be done BEFORE the start of the freeze-thaw cycle. It’s easy to forget unless it’s part of your seasonal maintenance. It’s important to realize that penetrating sealers are not permanent. They can be long-lasting, but their life will depend on acid exposure, which can break seals down over time. Acid can be introduced by acid rain or cleaning materials. Mold and mildew cleaners, while initially non-acidic, can generate acids as they break down, having an impact. For this reason, one should consider re-sealing every couple of years or partnering with a knowledgeable vendor who can review your site and the chemicals being introduced to highlight possible problems. MARBLELIFE-ENDURACRETE is such a company.
Regular Clearing: Prompt removal of snow and slush prevents the formation of ice layers. Consider where your meltwater will run. Consider the pH of cleaning materials and other chemicals that could contact the concrete, as acidic interactions could damage your seal in that area.
Use of Safe De-icing Agents: Choose de-icing products that are less harmful to stone and concrete materials. This is more about protecting your rebar if water reaches it, but even without salts, rebar won’t respond well to water.
Long-term Implications
Aesthetic Impact: Apart from structural damage, the aesthetic appeal of stone and concrete surfaces can be compromised, leading to a weathered and aged appearance. With concrete, this can result in surface pockmarks or cracks associated with rebar expansion as it rusts.
Safety Hazards: Uneven surfaces due to cracking and ice formation increase the risk of tripping as well as slips-and-falls.
Cost of Repairs and Maintenance: Frequent repairs and intensive maintenance are required to manage the deteriorating effects of slush on stone surfaces. While repairs are possible, they result in their own eyesore distractions, often leaving a patchwork appearance signaling to knowledgeable care providers that an issue exists within the property’s maintenance plan.
Common Types of Damage to Stone Floors and Concrete Driveways, Walkways, and Sidewalks
Stone floors and concrete surfaces endure significant stress during winter, exhibiting various types of damage that can compromise their integrity and aesthetics. Common issues include:
Pockmarks: These small, crater-like indentations appear when water trapped in the stone freezes and expands, exerting sufficient internal pressure to pop the concrete segment above the ice off the surface.
Cracks: These form when the expansion of frozen moisture inside the stone exceeds the material's tensile strength, causing it to fracture.
Spalling: This refers to the flaking or peeling off of the stone surface, often around the edges, due to moisture penetration and subsequent freeze-thaw cycles. Generally, this occurs when the water surface is beneath the stone or concrete and seeks to escape through the surface. The vapor pressure build-up weakens the material as it breaks down to the weakest point above it. These pressures are sufficient to push the vein in a marble floor out of the floor to release the pressure. For this reason, sealers must be moisture vapor permeable, or they can contribute to this type of failure. Waxes should never be used on a floor that sits on the ground for this reason. A broken sprinkler head could result in sufficient excess moisture vapor pressure to spall a floor or to salt-stain the surface.
Role of Salt and Slush in Damage
The presence of salt and slush exacerbates these issues. Salt delays the freeze-thaw process by lowering the freezing point of water, delaying its appearance until later in the season or later in the evening. What it doesn’t do is prevent ice from forming if the temperature drops below the new freeze point. How much salt impacts the freeze point depends on the amount of salt in the water. To drop the freezing point of a gallon of water from 32 to 26°F takes 0.5 pounds of rock salt. A gallon of water weighs roughly 8 lbs. That amounts to 6% by weight, which is a lot of salt. The most a gallon of water can hold is 2.25 lb, at which point we can approach 0°F. Obviously, we aren’t getting to such levels, but it demonstrates that there is a limit. If temperatures reach 0°F, all that water is ice, wherever it is at the time. We tend to think that salt eliminates the freeze problem when in truth, it delays it until later in the season in most northern climates.
Once damage or a crack is formed, water can create a larger space, and that 9% expansion becomes even more significant, which is why repairing damage is crucial, as it can accelerate unless it creates a new drainage for the water passing through it on melting.
Preventative Measures and Maintenance Tips
To mitigate the destructive impact of salt and slush, regular maintenance is critical:
Regular Cleaning: After any snowfall, promptly remove snow and slush from stone surfaces to prevent salt accumulation and reduce meltwater exposure during freezing temperature periods. Use a plastic shovel to avoid scratching the stone. Snow can be heavy—we get it. If possible, move snow and ice to the downside of the surface to reduce the amount of water that will run across the surface as temperatures peak above freezing again. That said, this is often more theoretical than practical. It is better to rest comfortably knowing your surface was sealed.
Effective Washing: Periodically, wash the stone surfaces with fresh water to dissolve and remove any residual salt. This practice helps minimize salt’s corrosive effects. You sealed it for a reason, but there’s no need to tempt fate. The problem with seals is that there are no outward signs of failure when they fail. We assume no acid comes into contact with our surface, but this may not be true. Spilling a Coke introduces a material with a pH of 2.3 (with 7 being neutral). That is VERY acidic. Outside, who is cleaning that up? No one, so it’s allowed to interact with your surface until it’s rinsed away, dries up, or reacts with the seal. Most penetrating sealers are silicate-based, and silicates in the presence of an acid can revert to their raw materials and be washed away. A local spill can impact the seal locally, but acid rain can do so across a broad area over time. For this reason, penetrating sealers may need to be re-applied over time. Warranties tend to have limitations associated with keeping the surface free of acid contact, which unfortunately may not be feasible. This is why we see concrete parking decks being resealed every 5 to 7 years. This is also why we see bridges failing due to delayed or forgotten seal maintenance.
Choosing the Right Cleaning Products
Select cleaning products that are specifically designed for use on stone and concrete. These products should effectively cleanse without damaging the stone’s protective sealant. Avoid acidic cleaners that could erode the stone surface. Recognize where acids might slip into your environment, such as the outside eating area of your food court, where Coke products can be routinely spilled, increasing the likelihood that periodic re-sealing is needed.
Importance of Sealing
Sealing stone and concrete surfaces is a crucial defensive strategy against the penetration of salts and moisture:
Sealant Application: Apply a high-quality penetrating sealant to stone and exterior concrete floors, driveways, sidewalks, and walkways to create a barrier against moisture penetration. This sealant not only protects against water and salt intrusion but also keeps staining materials from penetrating the surface, making it easier to keep them clean. When cleaning up a sticky spill, it’s always easier to wipe from the surface than to extract it from unsealed pores. The worst is the building guest who opts to change their oil in your parking lot. Unsealed, that oil soaks into the concrete, creating a stain. Every time it’s cleaned, the oil re-equilibrates out of the concrete and spreads across the unsealed surface. However, if sealed, this mess can be cat-littered and shoveled away with minimal staining (unless allowed to dwell). Remember that a seal is not perfect. Over time, standing liquids can find a way through. This is particularly true the larger the area one is managing, but with each application, those possibilities are reduced.
Regular Reapplication: Depending on exposure and the product used, reapply sealants every one to three years as recommended. Parking decks, which are generally covered, may reduce this frequency to 5 to 7 years. Consider conditions such as traffic levels and exposure to weather extremes when determining the frequency of reapplication.
Professional Consultation
For best results, consult with a hard surface stone and concrete care professional to select the appropriate penetrating sealer and determine the best maintenance schedule. Professionals can also offer services like deep cleaning and sealant application, ensuring thorough coverage and protection. Keep in mind that there are applicators and partners that will evaluate the surrounding environment to ascertain where other liquids could come into contact with your surface and change the frequency in that area, or benefit from a shift in liquid specifications to lower total property maintenance costs over time. Treating your building as a system is needed to achieve the best results. It benefits no one to optimize for a single problem and create a new one while doing so.
Choosing the Right Products for Winter Maintenance
Winter brings unique challenges to maintaining stone and concrete surfaces. The right care products are essential for protecting these materials from the harsh effects of salt and slush. MARBLELIFE ENDURACRETE, a leader in stone and concrete care, offers specialized products designed to extend the life and enhance the beauty of stone and concrete during the cold months. More importantly, they can assist you as you consider your property's needs and environment, and where unique challenges may exist that can be mitigated before they create new problems to address. Experience matters. There is no need to learn through the accumulation of scars when knowledgeable guidance based on experience can hasten your efforts to develop your long-term maintenance.
MARBLELIFE’s Key Winter Care Products
- MARBLELIFE EnduraSeal: This sealant is an excellent choice for stone and concrete surfaces. It provides a robust barrier against moisture and salt penetration, crucial for protecting surfaces during freeze-thaw cycles. EnduraSeal helps maintain the structural integrity of stone and concrete by preventing water from seeping into and damaging the material.
- MARBLELIFE MaxOut Cleaner: Specifically formulated for deep cleaning, MaxOut Cleaner effectively removes grime, salt residues, and other winter-related deposits from stone and concrete surfaces. It’s designed to be safe on sealed surfaces, ensuring that cleaning does not compromise the integrity of the sealant.
Benefits of Using MARBLELIFE Products
Using these products offers several advantages:
Enhanced Protection: Both EnduraSeal and MaxOut Cleaner provide an additional layer of protection against common winter damages, such as cracking and spalling. MaxOut clears the pores of built-up dirt and oil, allowing the penetration of EnduraSeal to seal, and avoids dirt and oil from preventing seals from bridging pores.
Ease of Maintenance: Regular use of these products makes routine cleaning easier and more effective, allowing for the removal of spills and harmful residues from the surface.
Longevity of Surfaces: By using appropriate care products, the life of stone and concrete surfaces can be significantly extended, preserving their appearance and functionality. Life is expanded by avoiding freeze-thaw damage, and appearance is improved by enhancing stain resistance.
Long-term Strategies to Protect Your Investment
Regular assessments by stone and concrete care professionals, such as those from MARBLELIFE-ENDURACRETE, are vital. These experts can evaluate the condition of your stone and concrete surfaces to identify early signs of freeze-thaw wear and tear, and possible neighboring factors to be considered. They provide customized advice on the best products and techniques for your specific situation.
Benefits of Regular Service
- Expert Guidance: MARBLELIFE-ENDURACRETE professionals are equipped with the knowledge to recommend the most effective maintenance routines and products for each of your stone, tile, and concrete surfaces within and around your property.
- Custom Solutions: Every stone and concrete installation is unique; professionals can tailor their services to meet individual needs and environmental conditions.
- Preventative Care: Regular servicing helps to prevent the onset of severe damage, reducing the need for costly repairs over the length of your building ownership.
If you have your property routinely cleaned to address mold and mildew staining, you might be interested in learning that as this class of cleaners breaks down, it can create an acidic by-product that, if not rinsed away, could impact seal longevity.
Scheduling Annual Maintenance
Scheduling annual maintenance before winter sets in is a proactive approach to stone and concrete care. This schedule ensures that:
- Preparations are Timely: Maintenance tasks such as sealing are best performed before the cold weather begins. The day after freezing temperatures commence may be too late.
- Issues are Addressed Early: Any damage from the previous winter can be repaired, preventing further deterioration. If damage has occurred, it is a clear sign that a sealing service is needed.
- Peace of Mind: Knowing your stone and concrete surfaces are prepared for winter lets you enjoy the season without worrying about potential spring damage surprises.
Conclusion: Protect Your Stone Surfaces This Winter
How we prepare for winter’s freezing weather can significantly impact our stone and concrete exterior surfaces. Failed exterior surface sealing can result in pockmarks. Open unrepaired cracks can allow additional damage from ice expansion and adjusting meltwater flow can result in spalling if water collects beneath building slabs due to harmful freeze-thaw cycles. To safeguard your stone floors and concrete, sidewalks, walkways, and driveways, proactive care is crucial. Regular cleaning, proper sealing, and the use of specialized products like MARBLELIFE Stone Sealer, MARBLELIFE EnduraSeal Concrete Sealer, and MARBLELIFE MaxOut Cleaner can extend the surfaces' pock-free appearance and enhance the property's aesthetic appeal.
Take action today by scheduling a FREE CONSULTATION with your local MARBLELIFE-ENDURACRETE representative for personalized care and maintenance plans to ensure your surfaces withstand the challenges of winter. Managing a portfolio of properties across the country? MARBLELIFE-ENDURACRETE has offices nationwide, allowing you to get recommendations customized to each location’s needs and considerations.
