The Hidden Threat to Your Epoxy Floor: Moisture Vapor Explained

If you're considering an epoxy coating for your concrete floor, you're probably looking for durability, aesthetics, and long-term value. But there’s a hidden issue that can threaten your investment, moisture vapor. Understanding how moisture vapor works and why it’s a concern for epoxy-coated floors can save you thousands in potential repairs down the road.

We know how frustrating it can be to invest in a floor coating only to face issues you didn’t anticipate. At CustomCrete, we've helped countless clients navigate these challenges, ensuring their floors remain protected and look great for years to come.

Whether you’ve experienced problems before or you're researching solutions for the first time, this article will help you understand what moisture vapor is, how it affects concrete coatings, and the options available to protect your floors.

What Is Moisture Vapor?

Moisture vapor is water in its gaseous form. Unlike liquid water, which can be seen as puddles or wet spots, moisture vapor is invisible and can pass through porous materials like concrete. Even though concrete looks and feels solid, it's full of microscopic pores that allow moisture vapor to travel through it.

This becomes a problem when you apply a coating like epoxy or a sealant on top of the concrete. If moisture vapor is present beneath the surface, it will eventually rise and create pressure underneath the coating. This pressure can cause the coating to bubble, crack, or peel… resulting in costly repairs or even the need to reapply the entire coating.

Why Does Moisture Vapor Matter for Epoxy Coatings?

Epoxy is one of the most popular and durable coatings for concrete floors, especially in commercial and industrial settings. It's hard, glossy, and can withstand heavy traffic. However, epoxy has one critical weakness: it's not breathable. This means that if moisture vapor tries to escape through the concrete slab, it has nowhere to go. Over time, the trapped moisture vapor will push against the epoxy coating, causing it to separate from the surface, a process called delamination.

Delamination can result in:

• Bubbles or blisters forming under the surface of the epoxy
• Cracks in the coating, which leads to further damage
• Peeling or flaking, where the coating completely detaches from the concrete

All of these issues compromise the strength and appearance of your epoxy floor, leading to expensive repairs. In industrial settings, delamination can even result in downtime for your business, adding further costs and inconvenience.

How Does Moisture Vapor Enter Concrete?

There are a few key sources of moisture vapor that can make their way into your concrete floor:

1. Mixing: When you initially mix concrete, there is water present.  Even after your concrete hardens and dries, water vapor can still be present in the slab for months.

2. Groundwater: Concrete in contact with the earth can absorb moisture from the ground, especially in areas with high water tables.

3. Humidity: High humidity levels in the environment can seep into concrete, where the moisture becomes trapped beneath the surface.

4. Rain or external water sources: Even if you don’t see standing water, rain, or other forms of moisture can find their way into concrete slabs over time, especially if there are cracks or other weaknesses.

Moisture vapor moves through the pores in the concrete and can build up pressure if it has nowhere to go. This is where your choice of flooring material or coating becomes crucial.

Why Skipping Moisture Mitigation Is a Risk

When people invest in an epoxy floor, they often want to avoid additional costs. The temptation to skip steps, especially moisture mitigation, can be strong. However, this is where a lot of costly mistakes are made. Even if your concrete floor doesn't show visible signs of moisture, moisture vapor could still be present, slowly rising and building pressure under the surface.

Skipping moisture mitigation or choosing not to test for moisture vapor is like playing a high-stakes game of chance. You may not notice any problems initially, but over time, moisture vapor can cause the floor coating to fail, costing you much more than you would have spent on preventive measures.

How Can You Protect Your Epoxy Floor from Moisture Vapor?

While moisture vapor can be a serious issue, there are several ways to protect your floor from damage. The key is understanding the risk factors and choosing the right solution for your specific needs. Here are the most common options:

Moisture Vapor Barriers

One of the most effective ways to prevent moisture vapor from damaging your epoxy floor is by applying a moisture vapor barrier before the epoxy coating. This barrier is designed to block moisture vapor from rising through the concrete, protecting the coating from delamination. Although adding a moisture vapor barrier does increase the upfront cost, it's a small price to pay compared to the cost of repairs down the line.

Urethane Cement

If you're looking for a more robust solution, urethane cement is another great option. Urethane cement is immune to moisture vapor damage because it can handle both moisture and temperature fluctuations. This makes it an excellent choice for areas where moisture vapor could be an issue, such as industrial kitchens, breweries, or food prep areas. While urethane cement has a higher upfront cost, it's virtually maintenance-free once installed, making it a long-term solution for high-traffic, high-moisture areas.

Polished Concrete

If you're not set on epoxy, polished concrete is another great option. It's a breathable surface, which means it allows moisture vapor to pass through without causing damage. Polished concrete floors are durable, easy to clean, and don’t require the same level of maintenance as coated floors. However, it may not have the same aesthetic appeal as epoxy, depending on the look you're going for.

Is Moisture Testing Worth It?

Not every concrete floor will require a moisture vapor barrier, but how do you know if your floor is at risk? The best way to gauge whether moisture vapor will be an issue is by testing the moisture levels in your concrete. At CustomCrete, we offer several moisture testing options to help you assess the risk before you commit to a coating.

• Tramex Surface Testing:

This quick, non-invasive test measures the moisture levels at the surface of your concrete. While not the most accurate method, it provides a good starting point if you're unsure about moisture issues.

• RH Probe Testing:

By drilling into the concrete and inserting probes at various depths, this test provides a more detailed picture of the moisture within the slab. This method is particularly useful for industrial settings where moisture vapor could be an issue.

• Calcium Chloride Testing:

This test measures how much moisture vapor is being emitted from the concrete. By placing a small dish of calcium chloride on the surface and sealing it, we can measure how much moisture is released over 72 hours.

Testing gives you valuable information, but keep in mind that no method is 100% foolproof. Environmental conditions, the age of the concrete, and even weather changes can all impact the moisture levels. However, knowing the moisture content in your floor will help you make an informed decision about whether to invest in moisture mitigation.

Don't Let Moisture Vapor Ruin Your Epoxy Floor

Moisture vapor may be invisible, but its effects are anything but. Skipping moisture mitigation could cost you dearly in the long run, especially if you invest in an epoxy coating for your floor. At CustomCrete, we specialize in helping you avoid these costly mistakes. Whether through moisture vapor barriers, urethane cement, or polished concrete, we have the right solution for your specific needs.

Want to learn more about moisture vapor and how to protect your concrete floor? Contact CustomCrete today. We’re here to help you make the best decision for your flooring project and protect your investment for years to come.