By When investing in epoxy flooring—whether for a garage, basement, or commercial space—you expect a beautiful, durable finish that lasts for years. But one hidden culprit can jeopardize your floor’s longevity and appearance: moisture in the concrete slab. Moisture-related failures are among the most common issues that plague epoxy coatings, leading to unsightly bubbling, peeling, or poor adhesion. Fortunately, modern moisture-mitigation systems provide reliable solutions that can prevent these problems before they start.
This blog post explores why moisture is such a challenge, how it affects epoxy flooring, and how moisture-mitigation systems can protect your investment.
The Hidden Threat: Moisture in Concrete
Concrete may look dry, but it’s actually a porous material that can contain or transmit moisture for years after it’s poured. Water vapor from the ground beneath a slab can migrate upward—a process called moisture vapor transmission (MVT). Even slabs that appear dry to the touch can emit enough vapor to cause serious problems for surface coatings like epoxy.
If not addressed, moisture can:
- Prevent epoxy from bonding properly to the concrete
- Cause the coating to blister or bubble as vapor tries to escape
- Lead to delamination (peeling away) of the epoxy layer
- Encourage mold growth beneath the flooring in severe cases
These issues aren’t just cosmetic—they can lead to costly repairs or require complete removal and replacement of the flooring system.
How Moisture-Mitigation Works
A moisture-mitigation system is designed to block moisture vapor from reaching the epoxy layer. Think of it as a protective shield between your concrete slab and your decorative or functional epoxy coating.
The most effective moisture-control systems use two-component epoxy or polyurethane membranes formulated to withstand high levels of vapor transmission. These systems:
- Penetrate and seal the concrete surface
- Chemically bond to the substrate
- Create a continuous, impermeable barrier that locks out moisture
Professionally installed moisture-mitigation products are tested to meet standards like ASTM F3010, ensuring they provide robust protection even in challenging conditions.
When is Moisture-Mitigation Necessary?
Moisture mitigation isn’t required for every project—but it’s essential in certain conditions:
- New concrete slabs: Fresh concrete can take months (or longer) to fully cure and stop emitting vapor. Applying epoxy too soon without mitigation can be a recipe for failure.
- Basements and below-grade spaces: These areas are particularly vulnerable to moisture migration from surrounding soil.
- Commercial spaces with high humidity or water exposure: Warehouses, food processing plants, and facilities with frequent washdowns often benefit from added moisture protection.
- Slabs without an effective vapor barrier underneath: Older buildings may lack modern under-slab membranes, increasing the risk of MVT.
Moisture Testing: The First Step
Before applying epoxy, professional installers should test the slab to assess moisture levels. Common methods include:
- Relative humidity (RH) probes: Inserted into the concrete, these sensors provide an accurate measure of internal moisture conditions.
- Calcium chloride (CaCl) kits: These measure the amount of moisture vapor emitted at the surface over a set period.
If readings exceed safe limits (typically above 75-85% RH, depending on the coating), a moisture-mitigation system is strongly recommended.
The Nexus Epoxy Advantage
At Nexus Epoxy Flooring, we take moisture challenges seriously. Our team uses advanced testing tools to evaluate your slab and identify hidden risks. If needed, we apply premium-grade moisture-mitigation membranes that meet industry standards and are compatible with our full range of epoxy flooring systems.
By addressing moisture at the source, we ensure your new flooring not only looks stunning on day one—but continues to perform for years to come, without unexpected failures.
Moisture-related flooring failures can be frustrating and expensive—but they’re also avoidable. By understanding the risks of moisture vapor and investing in proven mitigation solutions, you can enjoy the beauty and durability of epoxy flooring without worry.
If you’re planning an epoxy flooring project in your home or business, contact Nexus Epoxy Flooring for a professional assessment. We’ll help you choose the right solution for long-lasting results, even in the most demanding environments.
