Concrete Moisture Problems: Why Your Subfloor Keeps Failing
Understanding the Hidden Cause Behind Flooring Failures in Florida
If you’ve ever installed new flooring in your Florida home or commercial space only to see bubbling, lifting, or discoloration a few months later, there’s a good chance excess moisture in your concrete slab is to blame. In Florida, where humidity levels and rainfall are high year round, moisture is one of the most common (and expensive) flooring problems. Yet it’s also one of the most misunderstood.
At Aston Stuart, we’ve seen countless floors fail not because of bad materials but because the concrete underneath was too wet when the new system went down.
Let’s break down why moisture issues happen, how to spot them early, and what can be done to protect your investment.
Why Concrete Holds Moisture:
Even though concrete looks solid, it’s actually porous like a dense sponge. Water vapor constantly moves through it, especially in humid climates like Orlando or Miami.
Here’s what contributes to the problem:
Florida’s High Humidity – Moisture from the air seeps into concrete, especially in homes without proper vapor barriers.
Improper Drying Time – After a new pour or patch, slabs can take weeks longer to dry in Florida than in other regions.
No Vapor Barrier Under the Slab – Many older homes were built without moisture barriers, meaning vapor travels directly from the ground up into your flooring system.
Recent Water Damage – Flooding, plumbing leaks, or hurricane related damage can spike moisture levels well above safe limits.
So What Happens When Moisture Levels Are Too High?
When concrete moisture exceeds 4%, flooring adhesives, coatings, and finishes can’t properly bond. You may notice:
Bubbling or blistering in vinyl or epoxy coatings
Delamination where materials lift off the slab
White powder residue called efflorescence
Mold or mildew odor
Cracked or hollow sounding tile
These aren’t just cosmetic problems, they’re signs your flooring system is failing from the ground up.
How To Test and Prevent Moisture Issues:
Before any self leveling or flooring system is installed, on site moisture testing should be performed across multiple slab locations. Using digital meters, measure moisture percentages to ensure the slab is within safe limits.
Recently, during a walkthrough with a local general contractor in Orlando, we tested more than 30 points on a commercial slab — the average moisture reading was 14.8%, far above the acceptable 4%. In cases like that, we recommend applying a vapor barrier such as LATICRETE® Vapor Ban ER, a premium moisture mitigation system designed to seal the concrete before leveling or installing flooring.
Why Moisture Mitigation Is Worth It
While it’s tempting to skip the vapor barrier to save money upfront, it’s almost always more expensive to repair a failed floor later. A proper moisture control system:
Prevents costly rework
Extends the lifespan of your flooring
Improves adhesion and performance
Keeps your warranty valid
For most Florida flooring projects, the added cost of vapor mitigation is minor compared to the thousands you’d spend on replacements later.
Protect Your Floors the Right Way
Whether you’re a homeowner remodeling after water damage or a general contractor managing a commercial build, don’t overlook the importance of moisture and vapor control. At Aston Stuart, we provide moisture testing, vapor barrier installation, and professional self leveling across the state of Florida. Our goal is simple: a long lasting floor backed by proper preparation.
Schedule a Moisture Test Today!
Don’t risk another failed flooring job. Call us at 1-800-817-7385 or request an estimate at selflevelingflorida.com to schedule your moisture testing and leveling assessment today.
Let’s make sure your next floor starts and stays solid.