Moisture is the leading cause of concrete coating failures. It weakens adhesion, reduces thickness, and causes defects like blistering and peeling. Key findings:

• Epoxy coatings lose 43% adhesion strength and 34.45% thickness under moisture and freeze-thaw exposure.
• Water-based coatings perform worse, with 47% adhesion loss and 61.69% thickness reduction.
• Polyurea coatings resist moisture better, with faster curing times and higher flexibility (300–600% elongation).

In areas like North Idaho and Eastern Washington, harsh weather amplifies these issues. Polyurea systems, like those offered by Croc Coatings, provide stronger protection against moisture damage, especially in challenging climates. Proper moisture testing, surface preparation, and using moisture-tolerant primers are critical to long-lasting results.

How to Test for Moisture in Concrete + The Best Fix

How Moisture Affects Concrete Coating Performance

Concrete’s porous nature makes it vulnerable to moisture, allowing water to seep in and accumulate. Over time, this can weaken even the most durable coating systems.

Where Moisture Comes From

Moisture can infiltrate concrete in several ways. Groundwater is a common culprit, rising through the concrete via capillary action and bringing moisture from below the surface. Rainwater and surface water can also penetrate through cracks or poorly sealed areas, becoming trapped beneath the coating. Additionally, ambient humidity can condense on cooler concrete surfaces, while water vapor from freshly poured concrete can cause issues if coatings are applied before the material has fully cured.

Moisture typically enters concrete through capillary absorption, diffusion, or direct contact, all of which contribute to increasing internal water levels. These pathways set the stage for coating damage.

How Moisture Damages Coatings

Moisture intrusion doesn’t just affect adhesion – it can also lead to physical defects in the coating itself. Problems like blistering, peeling, and delamination occur when trapped moisture vaporizes, creating pressure beneath the coating surface. Small blisters can rapidly expand, causing the coating to separate from the concrete.

The table below highlights how different coating types respond to moisture and freeze-thaw conditions:

Coating Type	Adhesion Loss (Moisture + Freeze–Thaw)	Absorption Rate Increase	Thickness Loss
Epoxy	43%	146.73%	34.45%
Water-based	47%	171.16%	61.69%
Solvent-based	13.63%	247.54%	13.10%

The data shows that water-based coatings are particularly vulnerable, losing up to 62% of their thickness under moisture exposure, while epoxy coatings experience over 43% adhesion loss. Absorption rates can skyrocket by nearly 250% when coatings face moisture combined with harsh chemicals.

Moisture also contributes to alkali-silica reaction (ASR), where alkalis in the concrete react with silica in the presence of water. This reaction produces an expansive gel that creates internal pressure, leading to cracks and more pathways for moisture to enter. Similarly, shrinkage cracking occurs as water evaporates from concrete, causing the material to contract and form fissures that further weaken coatings.

Ultimately, high moisture levels drastically reduce the bond between coatings and concrete, leaving them more susceptible to mechanical stress and environmental changes.

Polyurea Coatings: Performance in Wet Conditions

Moisture damage is a common challenge for many traditional coatings, but polyurea systems stand out as a reliable alternative. Thanks to their unique chemical properties and fast curing times, polyurea coatings excel in wet environments where other options often fall short.

Why Polyurea Handles Moisture So Well

Polyurea coatings are built with a dense, cross-linked structure that acts as a barrier, blocking both water vapor and liquid water effectively. One of their standout features is their rapid curing time – ranging from just seconds to minutes. This quick setting process minimizes the chances of moisture interfering during application, making it especially useful in environments with changing humidity levels.

Another advantage is polyurea’s impressive flexibility, with an elongation range of 300–600%. This flexibility allows it to accommodate substrate movements, such as those caused by freeze-thaw cycles. For example, when concrete expands and contracts in response to temperature changes, polyurea coatings can stretch and move without cracking, maintaining their protective barrier.

Here’s a quick comparison of how polyurea stacks up against other common coatings:

Coating Type	Moisture Resistance	Curing Time	Flexibility	Water Absorption Rate
Polyurea	Excellent	Seconds–Minutes	High (300–600% elongation)	Markedly lower
Epoxy	Good–Moderate	Hours–Days	Moderate (approx. 2–5% elongation)	Higher
Acrylic	Moderate	Hours	Low	Highest

Unlike epoxy coatings, which can lose adhesion when exposed to moisture or freeze-thaw cycles, polyurea retains its structural integrity and barrier properties under similar conditions.

However, even with its many advantages, polyurea coatings are not completely immune to challenges posed by extreme moisture conditions.

Challenges with High Moisture Levels

While polyurea coatings offer excellent moisture resistance, their performance can be affected if the concrete substrate emits too much moisture vapor. Problems arise when the moisture vapor emission rate (MVER) exceeds 3–5 lbs per 1,000 sq ft in 24 hours. At these levels, issues like blistering, delamination, or weak adhesion can occur.

Proper surface preparation and moisture testing, such as ASTM F2170 or F1869, are critical to avoid these problems. High levels of trapped moisture beneath the coating can vaporize, leading to bubbling or even complete adhesion failure. Contractors dealing with high MVER levels should take precautions, such as applying a moisture mitigation primer or allowing the substrate more time to dry. Even polyurea formulations designed for "green" (recently poured) concrete require thorough moisture evaluation to prevent costly failures.

If moisture control is neglected, the resulting damage can be severe, often requiring complete removal and reapplication of the coating. This not only increases costs but also leads to longer project delays and downtime. Proper planning and preparation are key to ensuring polyurea coatings perform as intended, even in challenging wet conditions.

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How to Test and Control Moisture in Concrete

Getting moisture levels right in concrete is critical if you want your coatings to last. Even the most advanced polyurea systems can fail if moisture isn’t properly managed. By using the right testing methods and preventive strategies, you can avoid costly mistakes and headaches later on.

Standard Moisture Testing Methods

There are three main ways to test concrete for moisture, each offering different insights into the condition of the slab. Relative humidity (RH) probes are widely considered the most reliable method in the U.S., following ASTM F2170 standards. These probes are placed into drilled holes at a specific depth – usually 40% of the slab’s thickness for slabs drying from one side – and left to stabilize before taking measurements. This method gives an accurate picture of internal moisture levels, making it the go-to option for critical projects.

The calcium chloride test (ASTM F1869) is a more straightforward method that measures the moisture vapor emission rate (MVER) from the surface. To perform this test, a dish of calcium chloride is placed under a sealed dome on the concrete surface for 60 to 72 hours. The weight gain of the dish is then used to calculate vapor emission. While simple and commonly used, this method only captures surface-level moisture and can be affected by environmental conditions. It’s less dependable for thicker slabs or when deeper moisture is a concern.

Surface moisture meters provide a quick way to estimate moisture near the surface using electrical resistance or capacitance. These tools are great for preliminary checks over large areas but aren’t as effective for identifying deeper moisture or providing the detailed data needed for high-stakes installations.

Testing Method	What It Measures	Best Use Case	Limitations
RH Probe (ASTM F2170)	Internal humidity at depth	Critical installations, thick slabs	Requires drilling, takes time
Calcium Chloride (F1869)	Surface vapor emission	General screening, thin slabs	Surface-only, weather dependent
Surface Meter	Near-surface moisture	Quick checks, large areas	Less accurate for deep moisture

Choose the testing method based on the slab’s thickness and the level of accuracy you need. For high-performance polyurea coatings, RH probes are the most dependable choice. On the other hand, surface meters are useful for quick, initial scans before diving into more detailed testing.

The data you gather from these tests is the foundation for effective moisture control strategies.

How to Prevent Moisture Problems

Preventing moisture issues starts with proven strategies that protect your coatings from failure. One effective approach is using hydrophobic surface treatments. For instance, sodium acetate-based treatments can cut water absorption by up to 95% compared to untreated concrete. Other treatments, like silicate resins and fluoropolymers, also significantly reduce water absorption – by 69% in controlled tests.

Proper surface preparation is another essential step. This isn’t just about cleaning; it’s about creating the right conditions for moisture control. Techniques such as mechanical grinding, shot blasting, and thorough vacuuming remove contaminants, open up the concrete’s pores for better primer penetration, and ensure the substrate is clean and dry. This minimizes trapped moisture and boosts coating adhesion, tackling one of the main reasons coatings fail.

Environmental controls during installation are equally important. Maintaining the right temperature and humidity helps prevent condensation and moisture migration. Tools like dehumidifiers, heaters, or air conditioning systems can stabilize the environment, ensuring coatings cure correctly and stick to the surface as intended.

Water-repelling primers add an extra layer of defense against moisture. These specialized products, including silicate resins and hydrophobic treatments, reduce porosity and water absorption by creating a water-resistant barrier within the concrete. When applied correctly, they enhance the performance and longevity of the topcoat.

Skipping these preventive measures can lead to serious problems. Research shows that moisture exposure and freeze-thaw cycles can reduce adhesion strength by up to 47% and cut coating thickness by over 60% in some systems. Excess moisture can also drastically increase coating absorption – by 146.73% for epoxy systems, 247.54% for solvent-based coatings, and 171.16% for water-soluble systems when exposed to tough conditions.

To succeed in managing moisture, you need a well-rounded approach: thorough testing, meticulous preparation, and controlled environmental conditions during installation. Companies in regions with challenging climates, like North Idaho and Eastern Washington, know that these steps are essential for ensuring long-lasting coating performance.

Moisture Challenges in North Idaho and Eastern Washington

The Pacific Northwest is known for its tough weather conditions, which can wreak havoc on concrete coatings. High humidity, heavy precipitation, and freezing temperatures in this region create the perfect storm for moisture-related coating failures. To withstand these challenges, solutions must be durable and moisture-resistant.

Local Weather Effects on Concrete Coatings

In the Spokane, WA area, annual precipitation averages 16.5 inches, with heavy snowfall and freeze–thaw cycles dominating from November through March. These conditions put concrete coatings through the wringer, subjecting them to repeated moisture exposure, freezing, and rapid temperature fluctuations.

Freeze–thaw cycles are particularly damaging. They create internal pressure in the concrete, leading to microcracks, delamination, and eventual coating failure. Adding to the problem, the region’s high humidity and prolonged wet seasons can increase water absorption in concrete by over 100%. This moisture doesn’t just linger on the surface – it seeps deep into the slab, generating vapor pressure that causes blistering, bubbling, and peeling.

Daily and seasonal temperature swings further complicate matters. Concrete expands and contracts with these changes, and coatings that lack flexibility or strong adhesion often develop stress cracks. These cracks let moisture in, speeding up the deterioration process.

Some common issues in the region include garage floor coatings that peel after winter, patio surfaces that bubble from snowmelt, and basement floors that delaminate in areas with high groundwater. Traditional epoxy systems often fail under these conditions because they’re not built to handle the combination of moisture and temperature stresses seen in North Idaho and Eastern Washington. Clearly, these challenges call for specialized solutions.

Croc Coatings‘ Moisture Management Solutions

Croc Coatings has developed strategies tailored to these harsh conditions. Their Penntek Evolution system is built to handle the region’s demanding climate and is four times stronger than traditional epoxy.

The Penntek Evolution system uses advanced polyurea technology, which offers superior moisture resistance and flexibility. Unlike rigid epoxy, polyurea coatings can flex with the natural movement of concrete during freeze–thaw cycles, maintaining a strong, protective barrier.

Another standout feature is the system’s rapid curing time. While epoxy coatings can take 24–72 hours to cure, the Penntek Evolution system cures in just 1–2 hours. This quick turnaround minimizes the risk of moisture contamination during installation – a critical advantage in a region with unpredictable weather.

Before applying any coating, Croc Coatings conducts rigorous moisture testing using ASTM-approved methods like calcium chloride testing (ASTM F1869) and in-situ relative humidity measurements (ASTM F2170). These tests ensure the concrete slab is within acceptable moisture levels, reducing the risk of future failures caused by excessive moisture.

Their installation process also includes moisture-tolerant primers and thorough surface preparation. These primers create a water-resistant barrier within the concrete, reducing porosity and improving adhesion between the substrate and topcoat. This multi-layered approach provides extra protection against moisture intrusion.

Founded by Jim and Kelley Hobart, Croc Coatings serves both residential and commercial clients across North Idaho and Eastern Washington, including Spokane and the Tri-Cities. Their one-day installation process minimizes disruption while ensuring the coatings cure under ideal conditions. Plus, their lifetime warranty underscores their confidence in the system’s ability to perform in challenging environments.

The Penntek Evolution system is ideal for applications like garage floors, patios, pool decks, basements, and industrial floors – areas especially prone to moisture damage in this region. By combining cutting-edge materials with proven techniques, Croc Coatings offers a durable solution designed to withstand the Pacific Northwest’s demanding climate while delivering long-lasting performance.

Conclusion: Managing Moisture in Concrete Coatings

Effective moisture management is crucial for ensuring the longevity of concrete coatings. Studies consistently show that uncontrolled moisture can severely weaken adhesion and reduce durability, leading to frequent repairs and unnecessary expenses.

While traditional epoxy coatings often struggle with increased water absorption, polyurea systems have proven to maintain their performance over time. This difference can determine whether a coating lasts for decades or fails prematurely.

Standardized testing methods, such as ASTM F2170 and F1869, play a key role in identifying moisture-related risks. Hydrophobic treatments have shown impressive results, cutting water absorption by as much as 95% when compared to untreated concrete. These findings highlight the importance of taking proactive steps to manage moisture effectively.

For areas like North Idaho and Eastern Washington, where heavy precipitation, freeze–thaw cycles, and extreme temperature shifts are common, these insights are especially critical. Croc Coatings addresses these challenges head-on with ASTM-approved testing and the advanced Penntek Evolution system, designed to withstand harsh conditions. Their approach, which includes moisture-tolerant primers and meticulous surface preparation, aligns with the highest industry standards. Plus, their lifetime warranty underscores their confidence in the durability and performance of their solutions.

FAQs

How can you test moisture levels in concrete before applying a coating?

Testing the moisture levels in concrete is a critical step to ensure your coating adheres properly and lasts as long as it should. Here are some common methods to check for moisture:

• Plastic Sheet Test: Tape a plastic sheet to the concrete surface and leave it for 24 hours. If condensation forms underneath, it indicates excessive moisture.
• Calcium Chloride Test: This method gauges how much moisture is emitted from the concrete over a set period, providing a measurable result.
• Relative Humidity (RH) Probes: By inserting probes into drilled holes in the concrete, you can measure the moisture levels inside the slab itself.

Each method has its strengths, but for the most reliable results, it’s worth using professional-grade tools or consulting an expert. Proper moisture testing ensures your concrete is prepared for a durable coating, like the Penntek Evolution system from Croc Coatings, which is built to handle tough conditions.

How does polyurea perform compared to epoxy and water-based coatings when it comes to moisture resistance and flexibility?

Polyurea coatings stand out for their strong resistance to moisture and impressive flexibility, making them a go-to option for areas prone to humidity or water exposure. Unlike epoxy coatings, which can become brittle over time and struggle in damp environments, polyurea retains its strength and elasticity, even under tough conditions.

Croc Coatings takes this a step further with their exclusive Penntek Evolution industrial coating system. This system is four times stronger than epoxy and combines durability with long-lasting performance. It’s engineered to handle heavy use on surfaces like garage floors, patios, pool decks, and basements, all while delivering a polished, professional appearance.

How can I protect concrete coatings from moisture damage in areas with extreme weather?

When it comes to protecting concrete coatings from moisture damage in areas with extreme weather, choosing the right coating system is crucial. For example, Penntek Evolution industrial coating, available through Croc Coatings, offers outstanding durability – boasting a strength that’s four times greater than epoxy. This system is specifically crafted to endure tough environmental conditions.

Equally important is proper installation. Croc Coatings ensures a smooth and efficient application process, which is often completed in just one day. Plus, they stand behind their work with a lifetime warranty, offering long-term confidence. By combining advanced materials with expert installation, you can effectively shield your concrete surfaces from moisture damage, even in the harshest climates.

Related Blog Posts

• Humidity’s Impact on Floor Coatings
• How to Spot Defects in Concrete Coatings
• Top 5 Causes of Concrete Coating Failures
• Preventing Moisture-Related Coating Failures